All The President's Men
America's 45th President has been in post for just over six months, but in that short space of time Donald Trump's turbulent style has resulted in the loss of his National Security Adviser (Mike Flynn), Chief of Staff, (Reince Priebus), Press Secretary (Sean Spicer) and Chief Strategist (Steve Bannon).
So whoever said that 'Trump is to leadership what bulls are to China shops' was clearly understating the problem because as this photograph from the White House shows, of the six men gathered round the President's desk only Trump and his Vice President Mike Pence are left.
Donald Trump's latest recruit to the White House - his new communications director Anthony Scaramucci - seems to be an egg sandwich or two short of a picnic.
Here are some of the dumb things the "Mooch' said in a recent foul mouthed rant with a journalist from the New Yorker magazine.
On leaks and leakers
“I fired one guy the other day. I have three to four people I’ll fire tomorrow. I’ll get to the person who leaked that to you. Reince Priebus—if you want to leak something—he’ll be asked to resign very shortly.”
“What I want to do is I want to fucking kill all the leakers and I want to get the President’s agenda on track so we can succeed for the American people.”
“Reince is a fucking paranoid schizophrenic, a paranoiac.
“‘Oh, Bill Shine is coming in. Let me leak the fucking thing and see if I can cock-block these people the way I cock-blocked Scaramucci for six months."
“I’m not Steve Bannon, I’m not trying to suck my own cock.
“I’m not trying to build my own brand off the fucking strength of the President. I’m here to serve the country.”
The former director of the FBI, James Comey, is not a politician and has a reputation as a 'straight-shooter' having served two previous American presidents in George W Bush and Barack Obama before Donald Trump entered the White House.
The President initially showered praise on Mr Comey, but finally sacked the FBI director in the most prejudicial way after failing to pledge his 'loyalty' to Trump.
The BBC reports on a day of high drama in the American Congress where Comey made a point of emphasising the seriousness of Russia's meddling in the presidential election which Trump has still not condemned.
Comey: Trump White House 'lied' about the FBI
BBC US & Canada
Media caption - Comey's most revealing moments
Ex-FBI chief James Comey told Congress that the Trump administration's comments about him and the FBI were "lies plain and simple".
Mr Comey told a Senate committee they were wrong to denigrate the agency and its leadership.
He was also "confused" by the "shifting explanations" for his sacking, which came as he led a probe into any links between the Trump campaign and Moscow.
President Donald Trump later said he never sought to impede the inquiry.
Mr Trump's attorney, Marc Kasowitz, said in a statement Mr Comey's testimony "finally confirmed publicly" that the president was not under investigation as part of any probe in Russian political meddling.
In the statement, Mr Trump also denied asking Mr Comey for his loyalty or to drop an investigation into fired national security adviser Michael Flynn during private meetings.
In his testimony, Mr Comey said Mr Trump had repeatedly told him he was doing a "great" job.
He also suggested he was fired to "change the way the Russia investigation was being conducted".
The former FBI boss remained largely composed throughout almost three hours of testimony but became impassioned when delivering his opening remarks.
He told the panel that the White House "chose to defame me, and more importantly the FBI" by claiming the agency was "poorly led".
"Those were lies, plain and simple. And I'm so sorry that the FBI workforce had to hear them," he continued.
Media caption - A blockbuster that lived up to the hype. Watch the explosive first 10 minutes
"The FBI is honest. The FBI is strong. And the FBI is and always will be independent," he said in his opening remarks.
Mr Comey was leading one of several Russia investigations before Mr Trump fired him.
US intelligence agencies believe Russia interfered in the US election and they are investigating alleged links between the Trump campaign and Moscow.
But there is no known evidence of collusion and President Donald Trump has dismissed the story as "fake news".
His spokeswoman Sarah Sanders on Thursday hit back at Mr Comey, saying: "I can definitively say the president is not a liar."
Comey 'confused' by Clinton probe order
Key quotes in Comey prepared statement
The Trump-Russia story - in 200 words
"I was honestly concerned that he might lie about the nature of our meeting" he said.
Media caption - Comey hearing 'is our Super Bowl'
Media caption - Comey on Flynn conversation: "It's not for me to say if obstruction of justice"
During another meeting with Mr Trump, Mr Comey said the president appealed to him to "let go" an investigation into fired national security adviser Michael Flynn and his ties to the Kremlin.
After US media reported the conversation, the president warned Mr Comey in a tweet, saying he "better hope there are no 'tapes' of our conversations".
Mr Comey told the committee he hoped there were tapes, calling on Mr Trump to release them.
"The president surely knows whether he taped me, and if he did my feelings aren't hurt. Release all the tapes, I'm good with it," he said.
The White House has refused to say whether any such tapes exist.
Media caption - Comey: "Lordy I hope there are tapes"
After Mr Trump's tweet about potential tapes, Mr Comey said he realised it was important to release his own account of the story.
He revealed that he asked a "good friend of mine" who is a professor at Columbia Law School to share contents of the memo with a reporter, in order to build pressure for a special counsel.
As a result of this episode, former FBI chief Robert Mueller was appointed as special counsel to lead an independent investigation into the Trump campaign's potential ties to the Kremlin.
Mr Comey said he was "sure" Mr Mueller was also looking at whether Mr Trump obstructed justice.
Mr Trump attacked Mr Comey for leaking the documents, saying it showed that members of the US government are "actively attempting to undermine this administration".
What's the reaction?
"He's new in government, and so therefore I think he's learning as he goes," said Republican House Speaker Paul Ryan. "I'm not saying it's an acceptable excuse. It's just my observation."
"If you want to convict the president of being inappropriate, putting Comey in a bad spot, being rude, crude and a bull in a china shop, you would win," Senator Lindsey Graham told the BBC.
"The American people elected a bull in a china shop to help them with their lives, not this."
Democratic Senator Chris Murphy said "it's hard to overstate the impact of Jim Comey's testimony today" and that "it seems like the walls are closing in".
So whoever said that 'Trump is to leadership what bulls are to China shops' was clearly understating the problem because as this photograph from the White House shows, of the six men gathered round the President's desk only Trump and his Vice President Mike Pence are left.
All the President's Men (30/07/17)
Donald Trump's latest recruit to the White House - his new communications director Anthony Scaramucci - seems to be an egg sandwich or two short of a picnic.
Here are some of the dumb things the "Mooch' said in a recent foul mouthed rant with a journalist from the New Yorker magazine.
On leaks and leakers
“I fired one guy the other day. I have three to four people I’ll fire tomorrow. I’ll get to the person who leaked that to you. Reince Priebus—if you want to leak something—he’ll be asked to resign very shortly.”
“What I want to do is I want to fucking kill all the leakers and I want to get the President’s agenda on track so we can succeed for the American people.”
On Trump's chief of staff (Reince Priebus)
“Reince is a fucking paranoid schizophrenic, a paranoiac.
“‘Oh, Bill Shine is coming in. Let me leak the fucking thing and see if I can cock-block these people the way I cock-blocked Scaramucci for six months."
On Trump's chief strategist (Steve Bannon)
“I’m not Steve Bannon, I’m not trying to suck my own cock.
“I’m not trying to build my own brand off the fucking strength of the President. I’m here to serve the country.”
Now this may sound like 'locker room banter' to some people, but if you ask me this clown Scaramucci is not up to the serious business of government - it's almost as if he's auditioning for a part in 'Goodfellas'.
Is Trump An Idiot? (29/07/17)
Sarah
After sacking his own chief of staff (Reince Priebus) in less than six months an urgent question has to be asked:
The seat of American Government looks more and more like a 'mad house' these days with the President attacking the Attorney General Jeff Sessions whom Trump appointed only a few months ago.
Trump then makes matters worse by releasing his new attack dog Anthony Scaramucci (also known as the director of communications) who immediately savages the President's chief of staff, Reince Priebus, another of Trump's senior presidential appointments.
To round off a really miserable week at the Mad House, Trump lost a senate vote on his bill to kill off Obamacare after a dramatic intervention by Senator John McCain whom the President described as a 'bare American hero' earlier in the week.
The only conclusion to draw is that Donald Trump is a 'disaster'.
http://www.bbc.com/news/world-us-canada-40735613
Scaramucci challenges Priebus over leaks to the press
BBC US & Canada
Media caption - Emily Maitlis talks Trump, Russia... and chicken with Anthony Scaramucci
The newly-hired communications director for US President Donald Trump says he has a "very good idea" who the "senior leakers" are at the White House.
In a quickly-deleted tweet, and in interviews on Thursday, Anthony Scaramucci appeared to point the finger at Chief of Staff Reince Priebus.
"If Reince wants to explain that he's not a leaker, let him do that," he told CNN in a phone interview.
"He's gonna need to speak for his own actions", he added.
President Trump has said that leaks from the White House are a national security threat and must stop.
The tensions between two of his top aides appeared to be made public when Mr Scaramucci tweeted on Wednesday night that his government financial disclosure form had been leaked.
Image copyrightTWITTER @SCARAMUCCI
The tweet, which he subsequently deleted, ended by tagging Mr Priebus' Twitter handle.
After journalists began reporting that the tweet was a threat, Mr Scaramucci posted: "Wrong!
"Tweet was public notice to leakers that all Sr Adm officials are helping to end illegal leaks."
Feuding on live television
By Anthony Zurcher, BBC Washington
This is not how any of this is supposed to work. The newly installed White House communications director accusing - on Twitter! On a morning news show! - the White House chief of staff of criminal leaking.
In a White House that has been characterised by feuds and shifting centres of power, these latest developments may represent an attempt by Anthony Scaramucci - and others - to push out veteran Republican Party hands and clear the decks for Mr Trump's more unvarnished band of outsiders.
Press Secretary Sean Spicer and one of his top assistants are already gone. Reince Priebus could be next.
There's no telling how Mr Trump is taking all this. On one hand, he seems to have a visceral connection to Scaramucci, a brash New Yorker not unlike himself. On the other, the president hasn't always reacted well when subordinates step into his limelight.
Where Abraham Lincoln had his famous "team of rivals" in his administration, this is something different. Trump White House seems more akin to the final scene in Reservoir Dogs, where everyone is yelling and pointing a gun at someone else, and there's a good chance no one is going to come out unscathed.
Mr Preibus, who formerly chaired the Republican National Committee, and former White House spokesman Sean Spicer, had reportedly opposed the hiring of Mr Scaramucci.
Mr Spicer announced his resignation on the same day that Mr Scaramucci was hired.
"I don't know if [my relationship with Mr Preibus] is repairable or not," said Mr Scaramucci on Thursday. "That will be up to the president."
On his first day in the job last week, he told reporters that he and the chief of staff were personal friends who like "rough each other up" once in a while. "But he's a dear friend," he added.
Donald Trump is such a doofus that he's even started attacking people he appointed to his own cabinet just weeks ago.
Jeff Sessions, the US Attorney General, is the latest to attract Trump's out of control temper and this follows hot on the heels of the President sacking the highly respected FBU chief James Comey for not showing sufficient loyalty.
America's system of government is fast becoming a laughing stock around the world.
http://www.bbc.com/news/world-us-canada-40718076
Trump savages 'very weak' Attorney General Jeff Sessions
BBC US & Canada
President Donald Trump has launched yet another attack on US Attorney General Jeff Sessions, labelling him "weak".
His latest Twitter onslaught comes amid reports the president is consulting advisers about possibly firing the country's top prosecutor.
On Monday, he called Mr Sessions "beleaguered" in another tweet.
Mr Trump has made clear he is unhappy with Mr Sessions for recusing himself from an FBI inquiry into alleged Russian meddling in the 2016 election.
"Attorney General Jeff Sessions has taken a VERY weak position on Hillary Clinton crimes (where are E-mails & DNC server) & Intel leakers!" Mr Trump tweeted on Tuesday.
Moments earlier he questioned in another post why Mr Sessions was not looking into a report earlier this year that officials in Ukraine had sought to influence last year's US presidential election in favour of Mr Trump's Democratic rival.
The Washington Post reports that Mr Trump has asked an adviser how firing Mr Sessions would be received in the conservative media.
Anthony Scaramucci, the president's new communications director, fanned speculation on Tuesday that the attorney general's days could be numbered.
Conservative radio host Hugh Hewitt put it to Mr Scaramucci that it was pretty clear Mr Trump wants Mr Sessions gone.
"If there's this level of tension in the relationship that's public, you're probably right," Mr Scaramucci said.
Media caption'Alternative facts': 1984 on Broadway
Mr Sessions, known for his hardline anti-immigration stance, was one of then-candidate Mr Trump's earliest supporters in Washington.
But in March he recused himself from the Russia inquiry after failing during his confirmation hearing to disclose a meeting with the Kremlin's envoy.
If Mr Trump were to fire Mr Sessions, Deputy Attorney General Rod Rosenstein would take over the job on an acting basis.
Mr Trump has also been sharply critical of Mr Rosenstein for his handling of the Russia inquiry.
Some commentators suggest Mr Trump's ultimate target is Robert Mueller, the special counsel who is leading the Russia investigation.
3 Chief of Staffs in less than 3 years of being President: Part of the reason why @BarackObama can't manage to pass his agenda.
"Is Trump an idiot or is Trump an Idiot?"
Please send your answers to 1600 Pennsylvania Avenue, Washington DC.
Mad House v White House (28/07/17)
The seat of American Government looks more and more like a 'mad house' these days with the President attacking the Attorney General Jeff Sessions whom Trump appointed only a few months ago.
Trump then makes matters worse by releasing his new attack dog Anthony Scaramucci (also known as the director of communications) who immediately savages the President's chief of staff, Reince Priebus, another of Trump's senior presidential appointments.
To round off a really miserable week at the Mad House, Trump lost a senate vote on his bill to kill off Obamacare after a dramatic intervention by Senator John McCain whom the President described as a 'bare American hero' earlier in the week.
The only conclusion to draw is that Donald Trump is a 'disaster'.
http://www.bbc.com/news/world-us-canada-40735613
Scaramucci challenges Priebus over leaks to the press
BBC US & Canada
Media caption - Emily Maitlis talks Trump, Russia... and chicken with Anthony Scaramucci
The newly-hired communications director for US President Donald Trump says he has a "very good idea" who the "senior leakers" are at the White House.
In a quickly-deleted tweet, and in interviews on Thursday, Anthony Scaramucci appeared to point the finger at Chief of Staff Reince Priebus.
"If Reince wants to explain that he's not a leaker, let him do that," he told CNN in a phone interview.
"He's gonna need to speak for his own actions", he added.
President Trump has said that leaks from the White House are a national security threat and must stop.
The tensions between two of his top aides appeared to be made public when Mr Scaramucci tweeted on Wednesday night that his government financial disclosure form had been leaked.
Image copyrightTWITTER @SCARAMUCCIThe tweet, which he subsequently deleted, ended by tagging Mr Priebus' Twitter handle.
After journalists began reporting that the tweet was a threat, Mr Scaramucci posted: "Wrong!
"Tweet was public notice to leakers that all Sr Adm officials are helping to end illegal leaks."
Feuding on live television
By Anthony Zurcher, BBC Washington
This is not how any of this is supposed to work. The newly installed White House communications director accusing - on Twitter! On a morning news show! - the White House chief of staff of criminal leaking.
In a White House that has been characterised by feuds and shifting centres of power, these latest developments may represent an attempt by Anthony Scaramucci - and others - to push out veteran Republican Party hands and clear the decks for Mr Trump's more unvarnished band of outsiders.
Press Secretary Sean Spicer and one of his top assistants are already gone. Reince Priebus could be next.
There's no telling how Mr Trump is taking all this. On one hand, he seems to have a visceral connection to Scaramucci, a brash New Yorker not unlike himself. On the other, the president hasn't always reacted well when subordinates step into his limelight.
Where Abraham Lincoln had his famous "team of rivals" in his administration, this is something different. Trump White House seems more akin to the final scene in Reservoir Dogs, where everyone is yelling and pointing a gun at someone else, and there's a good chance no one is going to come out unscathed.
Wrong! Tweet was public notice to leakers that all Sr Adm officials are helping to end illegal leaks. @Reince45
Mr Preibus, who formerly chaired the Republican National Committee, and former White House spokesman Sean Spicer, had reportedly opposed the hiring of Mr Scaramucci.
Mr Spicer announced his resignation on the same day that Mr Scaramucci was hired.
"I don't know if [my relationship with Mr Preibus] is repairable or not," said Mr Scaramucci on Thursday. "That will be up to the president."
On his first day in the job last week, he told reporters that he and the chief of staff were personal friends who like "rough each other up" once in a while. "But he's a dear friend," he added.
Donald's Losing It (26/07/17)
Donald Trump is such a doofus that he's even started attacking people he appointed to his own cabinet just weeks ago.
Jeff Sessions, the US Attorney General, is the latest to attract Trump's out of control temper and this follows hot on the heels of the President sacking the highly respected FBU chief James Comey for not showing sufficient loyalty.
America's system of government is fast becoming a laughing stock around the world.
http://www.bbc.com/news/world-us-canada-40718076
Trump savages 'very weak' Attorney General Jeff Sessions
BBC US & Canada
President Donald Trump has launched yet another attack on US Attorney General Jeff Sessions, labelling him "weak".
His latest Twitter onslaught comes amid reports the president is consulting advisers about possibly firing the country's top prosecutor.
On Monday, he called Mr Sessions "beleaguered" in another tweet.
Mr Trump has made clear he is unhappy with Mr Sessions for recusing himself from an FBI inquiry into alleged Russian meddling in the 2016 election.
"Attorney General Jeff Sessions has taken a VERY weak position on Hillary Clinton crimes (where are E-mails & DNC server) & Intel leakers!" Mr Trump tweeted on Tuesday.
Moments earlier he questioned in another post why Mr Sessions was not looking into a report earlier this year that officials in Ukraine had sought to influence last year's US presidential election in favour of Mr Trump's Democratic rival.
The Washington Post reports that Mr Trump has asked an adviser how firing Mr Sessions would be received in the conservative media.
Anthony Scaramucci, the president's new communications director, fanned speculation on Tuesday that the attorney general's days could be numbered.
Conservative radio host Hugh Hewitt put it to Mr Scaramucci that it was pretty clear Mr Trump wants Mr Sessions gone.
"If there's this level of tension in the relationship that's public, you're probably right," Mr Scaramucci said.
No one is safe - Analysis, by Anthony Zurcher, BBC News
Like some sort of medieval torture device, the political pain applied to Attorney General Jeff Sessions is steadily increasing - and Donald Trump is behind it all, turning the screws.
After months of hints in the media that he wasn't happy with his attorney general, the president said last week that he wished he had never appointed his close campaign confidant. He then tweeted that the man was "beleaguered" and finally called him out by name as "very weak" in a latest round of tweets.
Mr Trump is apparently unhappy that his attorney general allowed the Russia investigation to morph into the ever-expanding independent counsel probe. And with each new revelation of the investigation's growing reach, the president has reacted more aggressively.
Last week's Bloomberg story that Robert Mueller and his team of veteran prosecutors are looking into the president's business dealings have been followed by this week's presidential Twitter tirades.
The campaign to undermine the attorney general could come at a high price, however. Reports circulate of an administration constantly looking over its shoulder.
If the president can turn on Mr Sessions, the thinking goes, no one is safe.
Mr Sessions was in the West Wing on Monday, but did not meet with the president, according to deputy press secretary Sarah Huckabee Sanders.
The attorney general has recently asked White House aides if he can meet Mr Trump to resolve their fallout, reports AP news agency.
But Mr Scaramucci said on Tuesday: "My guess is the president doesn't want to do that."
Like some sort of medieval torture device, the political pain applied to Attorney General Jeff Sessions is steadily increasing - and Donald Trump is behind it all, turning the screws.
After months of hints in the media that he wasn't happy with his attorney general, the president said last week that he wished he had never appointed his close campaign confidant. He then tweeted that the man was "beleaguered" and finally called him out by name as "very weak" in a latest round of tweets.
Mr Trump is apparently unhappy that his attorney general allowed the Russia investigation to morph into the ever-expanding independent counsel probe. And with each new revelation of the investigation's growing reach, the president has reacted more aggressively.
Last week's Bloomberg story that Robert Mueller and his team of veteran prosecutors are looking into the president's business dealings have been followed by this week's presidential Twitter tirades.
The campaign to undermine the attorney general could come at a high price, however. Reports circulate of an administration constantly looking over its shoulder.
If the president can turn on Mr Sessions, the thinking goes, no one is safe.
Mr Sessions was in the West Wing on Monday, but did not meet with the president, according to deputy press secretary Sarah Huckabee Sanders.
The attorney general has recently asked White House aides if he can meet Mr Trump to resolve their fallout, reports AP news agency.
But Mr Scaramucci said on Tuesday: "My guess is the president doesn't want to do that."
Image copyright - GETTY IMAGES Image caption - Attorney General Jeff Sessions was one of Mr Trump's earliest supporters in Washington
Last week, Mr Trump expressed regret about appointing the former Alabama senator to be top US prosecutor, telling the New York TimesMr Sessions "should have never recused himself".
It was reported on Monday that the president was considering replacing Mr Sessions with former New York Mayor Rudy Giuliani.
But Mr Giuliani told CNN on Monday that Mr Sessions had "made the right decision under the rules of the Justice Department" in recusing himself from the inquiry.
Last week, Mr Trump expressed regret about appointing the former Alabama senator to be top US prosecutor, telling the New York TimesMr Sessions "should have never recused himself".
It was reported on Monday that the president was considering replacing Mr Sessions with former New York Mayor Rudy Giuliani.
But Mr Giuliani told CNN on Monday that Mr Sessions had "made the right decision under the rules of the Justice Department" in recusing himself from the inquiry.
Media caption'Alternative facts': 1984 on Broadway
Mr Sessions, known for his hardline anti-immigration stance, was one of then-candidate Mr Trump's earliest supporters in Washington.
But in March he recused himself from the Russia inquiry after failing during his confirmation hearing to disclose a meeting with the Kremlin's envoy.
If Mr Trump were to fire Mr Sessions, Deputy Attorney General Rod Rosenstein would take over the job on an acting basis.
Mr Trump has also been sharply critical of Mr Rosenstein for his handling of the Russia inquiry.
Some commentators suggest Mr Trump's ultimate target is Robert Mueller, the special counsel who is leading the Russia investigation.
Special counsel: What is it?
Mr Sessions said last week he intended to stay in his post.
Mr Sessions said last week he intended to stay in his post.
Image copyright - AFP Image caption - Robert Mueller is leading the investigation into alleged Russian interference in the election
"I'm totally confident that we can continue to run this office in an effective way," he said.
Meanwhile, Mr Trump also appeared to suggest on Tuesday morning that the acting director of the FBI, Andrew McCabe, was corrupt.
He tweeted that Hillary Clinton gave $700,000 (£535,000) to Andrew McCabe's wife.
The president appeared to be referring to nearly $500,000 which Clinton ally and Virginia Governor Terry McAuliffe's political action committee donated to the Virginia state senate campaign of Dr Jill McCabe.
"I'm totally confident that we can continue to run this office in an effective way," he said.
Meanwhile, Mr Trump also appeared to suggest on Tuesday morning that the acting director of the FBI, Andrew McCabe, was corrupt.
He tweeted that Hillary Clinton gave $700,000 (£535,000) to Andrew McCabe's wife.
The president appeared to be referring to nearly $500,000 which Clinton ally and Virginia Governor Terry McAuliffe's political action committee donated to the Virginia state senate campaign of Dr Jill McCabe.
Trump is a 'Liar' (09/06/17)
The former director of the FBI, James Comey, is not a politician and has a reputation as a 'straight-shooter' having served two previous American presidents in George W Bush and Barack Obama before Donald Trump entered the White House.
The President initially showered praise on Mr Comey, but finally sacked the FBI director in the most prejudicial way after failing to pledge his 'loyalty' to Trump.
The BBC reports on a day of high drama in the American Congress where Comey made a point of emphasising the seriousness of Russia's meddling in the presidential election which Trump has still not condemned.
Comey: Trump White House 'lied' about the FBI
BBC US & Canada
Media caption - Comey's most revealing moments
Ex-FBI chief James Comey told Congress that the Trump administration's comments about him and the FBI were "lies plain and simple".
Mr Comey told a Senate committee they were wrong to denigrate the agency and its leadership.
He was also "confused" by the "shifting explanations" for his sacking, which came as he led a probe into any links between the Trump campaign and Moscow.
President Donald Trump later said he never sought to impede the inquiry.
Mr Trump's attorney, Marc Kasowitz, said in a statement Mr Comey's testimony "finally confirmed publicly" that the president was not under investigation as part of any probe in Russian political meddling.
In the statement, Mr Trump also denied asking Mr Comey for his loyalty or to drop an investigation into fired national security adviser Michael Flynn during private meetings.
In his testimony, Mr Comey said Mr Trump had repeatedly told him he was doing a "great" job.
He also suggested he was fired to "change the way the Russia investigation was being conducted".
The former FBI boss remained largely composed throughout almost three hours of testimony but became impassioned when delivering his opening remarks.
He told the panel that the White House "chose to defame me, and more importantly the FBI" by claiming the agency was "poorly led".
"Those were lies, plain and simple. And I'm so sorry that the FBI workforce had to hear them," he continued.
Media caption - A blockbuster that lived up to the hype. Watch the explosive first 10 minutes
"The FBI is honest. The FBI is strong. And the FBI is and always will be independent," he said in his opening remarks.
Mr Comey was leading one of several Russia investigations before Mr Trump fired him.
US intelligence agencies believe Russia interfered in the US election and they are investigating alleged links between the Trump campaign and Moscow.
But there is no known evidence of collusion and President Donald Trump has dismissed the story as "fake news".
His spokeswoman Sarah Sanders on Thursday hit back at Mr Comey, saying: "I can definitively say the president is not a liar."
'Staggering blow' for Trump - Anthony Zurcher, BBC News
For Donald Trump the good news from James Comey's testimony is that the former FBI director clearly said the president was not directly under FBI investigation at the time he was fired. The bad news was, well, everything else.
On multiple occasions, Mr Comey said he was either concerned or knew that the president or his administration was lying "plain and simple" - about the circumstances of his dismissal and about the nature of his meetings with the president.
It's clear the president woefully mishandled this, for which he has paid a high price ever since. By unceremoniously sacking him, and offering a muddle of explanations for it, he created an adversary with both the means and the motivation to respond in the most damaging way.
Mr Comey had a friend leak disturbing information about the president's actions to the media. He was given the biggest spotlight in a generation to publicly air further details. He stood before a Senate committee not just to defend himself, but also the honour of the FBI.
The White House may claim today's testimony is a technical exoneration. Politically, however, it's a staggering blow. And when it comes to the presidency, politics is everything.
For Donald Trump the good news from James Comey's testimony is that the former FBI director clearly said the president was not directly under FBI investigation at the time he was fired. The bad news was, well, everything else.
On multiple occasions, Mr Comey said he was either concerned or knew that the president or his administration was lying "plain and simple" - about the circumstances of his dismissal and about the nature of his meetings with the president.
It's clear the president woefully mishandled this, for which he has paid a high price ever since. By unceremoniously sacking him, and offering a muddle of explanations for it, he created an adversary with both the means and the motivation to respond in the most damaging way.
Mr Comey had a friend leak disturbing information about the president's actions to the media. He was given the biggest spotlight in a generation to publicly air further details. He stood before a Senate committee not just to defend himself, but also the honour of the FBI.
The White House may claim today's testimony is a technical exoneration. Politically, however, it's a staggering blow. And when it comes to the presidency, politics is everything.
Image copyright - REUTERS Image caption - Man in the spotlight - Comey takes the oath
During Thursday's testimony, Mr Comey emphasised that Russia's political meddling was "not a close call", adding: "There should be no fuzz on this whatsoever."
When asked by the Senate Intelligence Committee whether the president tried to stop the Russia investigation, Mr Comey said: "Not to my understanding, no."
He said he it was not for him to say whether Mr Trump's actions were an obstruction of justice.
Democratic Senator Mark Warner, the committee's vice chairman, pressed Mr Comey on why he decided to keep a record of his conversations with Mr Trump.
During Thursday's testimony, Mr Comey emphasised that Russia's political meddling was "not a close call", adding: "There should be no fuzz on this whatsoever."
When asked by the Senate Intelligence Committee whether the president tried to stop the Russia investigation, Mr Comey said: "Not to my understanding, no."
He said he it was not for him to say whether Mr Trump's actions were an obstruction of justice.
Democratic Senator Mark Warner, the committee's vice chairman, pressed Mr Comey on why he decided to keep a record of his conversations with Mr Trump.
Comey 'confused' by Clinton probe order
Key quotes in Comey prepared statement
The Trump-Russia story - in 200 words
"I was honestly concerned that he might lie about the nature of our meeting" he said.
Media caption - Comey hearing 'is our Super Bowl'
James Comey: From 'brave' to fired
Russia: The scandal Trump can't shake
How Trump's Russia trouble unfolded
Mr Comey, who published his prepared remarks a day before the hearing, detailed one meeting with Mr Trump in which the president asked Attorney General Jeff Sessions and White House aide Jared Kushner to leave the Oval Office.
"I knew something was about to happen that I needed to pay very close attention to," he said. "I remember thinking that that was a very disturbing development."
Russia: The scandal Trump can't shake
How Trump's Russia trouble unfolded
Mr Comey, who published his prepared remarks a day before the hearing, detailed one meeting with Mr Trump in which the president asked Attorney General Jeff Sessions and White House aide Jared Kushner to leave the Oval Office.
"I knew something was about to happen that I needed to pay very close attention to," he said. "I remember thinking that that was a very disturbing development."
Media caption - Comey on Flynn conversation: "It's not for me to say if obstruction of justice"
During another meeting with Mr Trump, Mr Comey said the president appealed to him to "let go" an investigation into fired national security adviser Michael Flynn and his ties to the Kremlin.
After US media reported the conversation, the president warned Mr Comey in a tweet, saying he "better hope there are no 'tapes' of our conversations".
Mr Comey told the committee he hoped there were tapes, calling on Mr Trump to release them.
"The president surely knows whether he taped me, and if he did my feelings aren't hurt. Release all the tapes, I'm good with it," he said.
The White House has refused to say whether any such tapes exist.
Media caption - Comey: "Lordy I hope there are tapes"
After Mr Trump's tweet about potential tapes, Mr Comey said he realised it was important to release his own account of the story.
He revealed that he asked a "good friend of mine" who is a professor at Columbia Law School to share contents of the memo with a reporter, in order to build pressure for a special counsel.
As a result of this episode, former FBI chief Robert Mueller was appointed as special counsel to lead an independent investigation into the Trump campaign's potential ties to the Kremlin.
Mr Comey said he was "sure" Mr Mueller was also looking at whether Mr Trump obstructed justice.
Mr Trump attacked Mr Comey for leaking the documents, saying it showed that members of the US government are "actively attempting to undermine this administration".
What's the reaction?
"He's new in government, and so therefore I think he's learning as he goes," said Republican House Speaker Paul Ryan. "I'm not saying it's an acceptable excuse. It's just my observation."
"If you want to convict the president of being inappropriate, putting Comey in a bad spot, being rude, crude and a bull in a china shop, you would win," Senator Lindsey Graham told the BBC.
"The American people elected a bull in a china shop to help them with their lives, not this."
Democratic Senator Chris Murphy said "it's hard to overstate the impact of Jim Comey's testimony today" and that "it seems like the walls are closing in".
