Comey also reportedly filed a memo after a February 14 White House meeting in which he claimed that Trump asked him to end the FBI's investigation into former national security adviser Michael Flynn.
In addition to the FBI investigation, the Senate and House Intelligence Committees are also conducting their own investigations into Russian Federation.
The White House has struggled to explain the chain of events that led to Mr Comey's firing and exactly who made the decision.
"If any president tries to impede an investigation - any president, no matter who it is - by interfering with the FBI, yes, that would be problematic". Comey's sacking triggered a political firestorm with an angry opposition calling for an appointment of a special prosecutor to investigate the alleged Russian influence in last year's general elections. "And that created a compromise situation, a situation where the national security adviser essentially could be blackmailed by the Russians".
NY [U.S.] May 20: Former FBI Director James Comey, who was sacked by the U.S. President, Donald Trump, amid an agency probe into Russian allegedly meddling in the U.S. election, has agreed to testify before the U.S. Senate Intelligence committee at a public hearing. The White House has given different versions of the reasons for the dismissal.
Trump supporters will assert that this was just an honest expression of Trump's legitimate foreign policy objective, a peaceful alliance with the Russians and the elimination of an incompetent Federal Bureau of Investigation director.
At first, the White House said Trump fired Comey based on the recommendation of the Justice Department, and because of Comey's handling of the FBI investigation into Hillary Clinton previous year.
Ousted former FBI Director James Comey has agreed to testify in an open hearing before the Senate Intelligence Committee, promising added sunlight on festering controversies that continues to plague President Donald Trump's administration. In the Oval Office weeks later, Comey told associates, the president asked him to shut down an investigation into Flynn.
Describing Trump as an "extremely sloppy operator", Blumenthal called his administration "inept" in "putting out fires" amid reported allegations and mixed messaging following the "terrible" handling of Comey's firing.
Chaffetz, who announced Thursday he was leaving Congress at the end of June, has requested Comey's memos, along with the Senate Judiciary Committee.More news: Mining magnate Andrew 'Twiggy' Forrest donates $400 million to Australian charities
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"There is no collusion between certainly myself and my campaign, but I can always speak for myself, and the Russians - zero", Trump told reporters.
The White House repeated its assertion that a "thorough investigation will confirm that there was no collusion between the campaign and any foreign entity".
Mr Trump met with the Russians on 10 May - the day after Mr Comey was sacked.
The latest crisis to beset Trump comes days after an another revelation by the daily which claimed that the president has asked sacked FBI director James Comey to end the agency's investigation into ties between his former national security adviser Mike Flynn and Russian Federation.
Comey, who was leading an FBI investigation into Trump's campaign team and whether it colluded with the Kremlin during the 2016 election, was sacked earlier this month. "He was insane, a real nut job", Mr. Trump said, according to a record of the meeting between Trump and the Russians that the New York Times obtained.
"The President has always emphasized the importance of making deals with Russian Federation as it relates to Syria, Ukraine, defeating ISIS and other key issues for the benefit and safety of the American people", Spicer said.
Both said that Trump's remarks had been misinterpreted. "Once again, the real story is that our national security has been undermined by the leaking of private and highly classified conversations". In March, Kushner volunteered to answer lawmakers' questions about meetings he had with Russian officials during the transition.
Since there has not been such a situation earlier, it could still be possible the newly appointed special counsel Robert Mueller would object to the former FBI director speaking in public about an ongoing investigation.
Senator Lindsey Graham said Thursday the appointment of a special counsel meant "Congress's ability to conduct investigations of all things Russian Federation has been severely limited".