Former FBI Director James Comey has accused the Trump administration of defaming him, but declined to offer his opinion on whether President Donald Trump sought to obstruct justice by asking him to drop an investigation into the former national security advisor.

The hearing could have significant repercussions for Mr. Trump’s presidency as special counsel Robert Mueller and several congressional committees investigate alleged Russian efforts to influence the 2016 presidential election and whether Trump's campaign colluded with this.

Mr. Trump fired the FBI chief on May 9, 2017 setting off a political fire storm, and he has since called Mr. Comey a “showboat” and a "grandstander”.

Live updates

10.35 p.m.: Mr. Trump, in a speech across town from the closely watched congressional hearing, tells supporters their movement was “under siege” and vowed to fight on. “We're under siege... but we will come out bigger and better and stronger than ever,” he says during a separate speech in Washington. “We will not back down from doing what is right ...we know how to fight and we will never give up.”

10.20 p.m.: Ms. Sanders says she doesn’t know if Mr. Trump is taping his Oval Office conversations, but will “try to look under the couch”.

Mr. Trump tweeted last month that Mr. Comey better hope there are no “tapes” of their conversations. Mr. Comey, testifying on Capitol Hill, said he indeed hoped tapes existed and called on the President to release them if they do. The White House has refused to answer what the President was referring to in his tweet. Spokeswoman says that she had “no idea” about Oval Office taping.

10.15 p.m.: A Columbia University law professor and close friend of Mr. Comey has confirmed he leaked contents of one of Comey’s memos to The New York Times. Mr. Comey testified before the Senate intelligence committee that he hoped the story about his interactions with Mr. Trump would prompt the appointment of a special counsel. Daniel Richman confirmed to The Associated Press in an email that he was the friend who Comey mentioned in his testimony. He declined further comment. Mr. Richman served with Mr. Comey in the Southern District of New York and at the FBI.

10.10 p.m.: The Senate Intelligence Committee’s hearing on Mr. Comey has ended public session. Mr. Comey now goes into a closed session with the Senators.

10.05 p.m.: A White House spokeswoman says Mr. Trump is “not a liar”. Trump spokeswoman Sarah Huckabee Sanders disputes Mr. Comey’s testimony when asked about it during an off-camera briefing at the White House, saying “I can definitely say the President’s not a liar.”

9.35 p.m: Mr. Comey says he does not know if Mr. Trump’s comments to him rise to level of obstruction of justice adding it's for the special counsel to decide. However, he won't say if he believed Mr. Trump colluded with Russia.

9.30 p.m.: Mr. Comey says he asked a friend to leak the contents of his memo about meetings with Mr. Trump. He says that he felt that releasing the details of his private conversations with the President might prompt the appointment of a special counsel in the case. He made the decision after Mr. Trump tweeted that Mr. Comey should hope there aren’t any tapes, he adds.

Comey says the contents of the memo were released to a reporter by a close friend of his who is a professor at Columbia law school.

9. 20 p.m.: Reaction — U.S. House Speaker Paul Ryan says Mr. Trump “was new at this” and probably was not “steeped” in FBI independence from White House.

9.15 p.m.: Mr. Comey says he felt free as private citizen to share his unclassifed memo on the Trump conversation with lawyer friend.

9.05 p.m.: Mr. Comey says he knew of a “variety of reasons” why Attorney General Jeff Sessions’ involvement in the Russia investigation would be problematic before Mr. Sessions recused himself in March. But Mr. Comey says the reasons are such “that I can’t discuss in an open setting.”

Mr. Comey says he doesn’t know if he thought Mr. Sessions had adhered to that recusal. He adds that that depends on the real reason for Mr. Comey’s firing, which Mr. Sessions had recommended.

9.00 p.m.: Explaining why he was reluctant to announce that Trump was not under investigation, Comey says he didn’t doing it because “it creates a duty to correct, which I’ve lived before.”

That’s a reference to the investigation into Hillary Clinton emails when Comey said late in the 2016 presidential campaign that the FBI was further investigating the case.

Comey also adds that he had asked a friend to share the content of his memo of his conversation with Trump to the press, says he believed that sharing the memo might lead to the appointment of a special counsel. Comey also adds that he did not discuss Russian interference in U.S. Election with Trump after first meeting.

8. 50 p.m.: "FBI thought U.S. Attorney General Jeff Sessions would recuse himself from Russia probe for ‘variety of reasons," said Comey. He says he knew of a “variety of reasons” why Attorney General Jeff Sessions’ involvement in the Russia investigation would be problematic before Sessions recused himself in March.

But Comey said during his Senate testimony the reasons are such “that I can’t discuss in an open setting.”

He also hoped that tapes of his conversations with President Donald Trump existed. Three days after Trump fired Comey, the president tweeted that Comey should hope there are “no tapes” of their conversations.

Comey documented his conversations with Trump in memos after the encounters. During his first public appearance since he was fired, senators asked Comey about his responses to Trump.

Comey says he chose his words carefully when responding to Trump because he was “so stunned” by the conversation. Comey was recalling a February conversation in which, Comey says, Trump said he hoped Comey could let go the FBI’s investigation into Trump’s first national security adviser Michael Flynn.

8.45 p.m.: Mr. Trump has so far stayed off Twitter during Mr. Comey’s testimony. But his eldest son hasn’t. Donald Trump Jr. is posting repeatedly during the closely watched testimony. Mr. Trump Jr. in particular seized on Mr. Comey’s assertion that he interpreted the President’s statement that he “hoped” the FBI would drop its probe into Mr. Flynn. Mr. Trump Jr. tweets “you would think a guy like Comey” would know the difference between “hoping and telling.” Mr. Trump Jr. and his brother Eric are now at the helm of their father’s New York-based business.

8.40 p.m.: Mr. Comey says he took “as a direction” Mr. Trump’s remark that he hoped Mr. Comey would drop an investigation into former NSA Mr. Flynn. Republican Senator James Risch of Idaho asks if Mr. Comey was aware of anyone being charged with obstruction of justice because they expressed hope for a certain outcome. Mr. Comey says he wasn’t. But Mr. Comey adds, “I took it as a direction,” and notes that the remark came during a one-on-one meeting with the President.

8.30 p.m.: Mr. Comey says he was stunned by Oval Office conversation with Mr. Trump about Mr. Flynn; adds relationship with Mr. Trump did not get off to good start because of the Jan. 6 conversation; Mr. Comey says he takes Mr. Trump “at his word” that he was fired because of the Russia investigation.

8.15 p.m.: I was confused when ex-AG Lynch instructed me to refer to the Hillary Clinton email case as “matter,” not “investigation”, says Mr. Comey; says he believed Mr. Trump was trying to build a relationship of loyalty in context of asking him to stay as Director at January 27, 2017 dinner; common sense told me Mr. Trump was looking to get something in exchange for me keeping the FBI job, he adds.

8.10 p.m.: Mr. Comey says he knew there might come a day when he would need a record to defend himself, FBI; He was concerned Mr. Trump might lie about their private meeting on January 6, 2017, he adds. However, he did not feel need to document private conversations with previous U.S. Presidents George Bush, Barack Obama.

8 p.m.: Mr. Comey says FBI became aware of Russia cyber intrusion in late summer of 2015. Trump administration chose to ‘defame’ me and FBI using ‘lies, plain and simple’, he says.

Former FBI Director James Comey speaks during a Senate Intelligence Committee hearing on Capitol Hill on June 8, 2017. | Photo Credit: AP

7.56 p.m.: Shifting explanations of my firing confused and concerned me, says Comey. He says says special counsel did not review or edit his written testimony and that he’s confident no votes cast in 2016 election were altered. He says he has no doubt Russia interfered with U.S. election.

7.53 p.m.: Democratic Senator Warner says accounts of Mr. Trump depict behavior in which a president should not engage.

7.51 p.m.: Mr. Comey has begun his much-anticipated congressional testimony under oath. Mr. Comey is expected to recount a series of interactions with President Donald Trump in the weeks before his firing that he will say made him uncomfortable. Those include a January dinner in which he says Trump asked him for his loyalty, and a White House conversation weeks later in which he says Mr. Trump asked him to end an investigation into former national security adviser Michael Flynn. Comey is testifying before the Senate intelligence committee. His remarks are his first public statements since his firing on May 9, which came as he was leading an FBI investigation into potential coordination between Russia and the Trump campaign.

7.45 p.m.: Mr. Trump will dispute key parts of Mr. Comey’s testimony. That’s according to a person close to the President’s legal team.

The person says the President disputes Mr. Comey’s claim that he asked him for loyalty. Mr. Trump also disputes Mr. Comey’s account of a conversation about the investigation into former NSA Flynn.

The person demanded anonymity because the person is not authorised to be named in a discussion about legal strategy.

7.40 p.m.: Top Committee Democrat Mark Warner says we cannot let anything or anyone prevent us from getting to bottom of Russia’s alleged role in U.S. election. Mr. Comey’s firing by Mr. Trump was shocking, he adds.

7.36 p.m.: Mr. Comey arrives in Senate hearing room for long-awaited testimony about interactions with Mr. Trump.

Former FBI Director James Comey listens to the committee chairman at the beginning of the Senate Intelligence Committee hearing on Capitol Hill on June 8, 2017. | Photo Credit: AP

7.30 p.m.: Mr. Trump’s outside counsel Marc Kasowitz will be at the White House to monitor Mr. Comey’s testimony. The President is expected to watch some of Mr. Comey’s remarks to lawmakers. His public schedule is largely clear until the afternoon.

Kasowitz is a longtime Trump lawyer. He was recently tapped to handle all inquiries related to the investigations into possible ties between Trump’s campaign and Russia a move intended to distance the White House from the FBI and congressional probes.

7.15 p.m.: Washington D.C. knows how to do big hearings even Titanic ones. Dramatic congressional hearings are something of a Washington art form, a rite of democracy carefully crafted for the cameras. A look at past high-drama hearings.

7 p.m.: U.S. television networks are setting aside regular programming, as the the moment will be hard for most Americans to miss. CNN has already kept a “countdown clock” to the start of Mr. Comey’s appearance before the Senate intelligence committee on its screen for days. The moment has already drawn comparisons to past congressional appearances that riveted the country, from Watergate to Anita Hill’s testimony at Clarence Thomas’ Supreme Court confirmation hearing.

“This is one of those moments where much of the country may want to stop and watch,” said Norah O’Donnell, part of the trio anchoring CBS’ live coverage. Lester Holt, Savannah Guthrie and Chuck Todd will be at the helm of NBC’s coverage. George Stephanopoulos anchors at ABC. Ms. O’Donnell’s fellow hosts at “CBS This Morning,” Gayle King and Charlie Rose, will be in the lead at that network. At Fox News Channel, Bill Hemmer and Shannon Bream will co-anchor. Wolf Blitzer and Anderson Cooper are the helm at CNN, with Brian Williams and Nicolle Wallace filling that role on MSNBC. C-SPAN will air the coverage on two of its channels. Facebook is offering live streams from several media outlets, including Buzzfeed, Townhall Media, Politico, The New York Times and Washington Post.

6.45 p.m.: The top Democrat on the Senate Intelligence Committee Mark Warner is of the opinion that the Comey testimony showed Mr. Trump appeared to threaten his job and asked him to drop an investigation into a senior aide, violating clear guidelines designed to prevent political interference into FBI probes. “The testimony that Mr. Comey has submitted for todays hearing is disturbing,” Mr. Warner will say in his opening statement at a committee hearing, according to excerpts obtained by Reuters.

6.35 p.m.: Mr. Comey’s statement on Wednesday fuelled fresh allegations that Mr. Trump illegally tried to obstruct an investigation into Russian interference in the 2016 election. In his statement ahead of his testimony, Mr. Comey detailed how Mr. Trump repeatedly raised the Russia case with him earlier this year, asking him to go easy on former national security advisor Michael Flynn, who is accused of improper links to Moscow. Trump complained the investigation was a "cloud" over his administration that needed to be lifted, Mr. Comey said.

And at a private White House dinner on January 27, just days after the Republican billionaire took office, Mr. Comey said Mr. Trump appeared to want to "create some sort of patronage relationship" with him.

"The president said, 'I need loyalty, I expect loyalty.' I didn't move, speak, or change my facial expression in any way during the awkward silence that followed," Mr. Comey said.

Mr. Comey did not say whether he thought the president's actions amounted to obstruction, a serious crime that could lead to impeachment. But he called Trump's approaches "very concerning, given the FBI's role as an independent investigative agency."

He also described trying to insulate himself and the Federal Bureau of Investigation from political pressure in the weeks before Trump fired him on May 9, as the president complained about the Russian probe and labelled it "fake news."

Mr. Comey said Mr. Trump told him during a one-on-one dinner on January 27, 2017 that he needed “loyalty”.

With inputs from AP, Reuters and AFP