Earlier this week, NPR confirmed that Trump had asked Comey to scuttle the investigation into his former national security adviser, Michael Flynn, according to a memo of the account written by Comey.
Former FBI Director James Comey, who was sacked by U.S. President Donald Trump last week amid an agency probe into alleged Russian meddling in the U.S. election, has agreed to testify before the U.S. Senate Intelligence Committee at a public hearing, the committee said in a statement on Friday.
Also, the New York Times reported on Friday that Trump had told top Russian diplomats who visited the Oval Office last week that firing Comey relieved "great pressure" on him.
In a press release in response to the Times story, the White House disputed not the facts of the report, but the interpretation, saying Trump was talking not about the FBI's criminal investigation into possible collusion between Russian Federation and the Trump campaign, but about post-election scrutiny that was making it hard for him to work with Russian Federation. "He was insane, a real nut job", Mr Trump said, according to a document detailing the Russian visit. Panel Chairman Richard Burr and Vice Chairman Mark Warner said they will schedule the hearing for after Memorial Day.
Trump, accompanied by wife Melania, walk across the South Lawn of the White House in Washington on Friday.
"I hope that former Director Comey's testimony will help answer some of the questions that have arisen since Director Comey was so suddenly dismissed by the President", Warner, a Democrat, said. Comey's associates have said that Trump asked the former Federal Bureau of Investigation chief for a pledge of loyalty during one meeting.
The developments were a blow to White House efforts to tamp down interest in the Russian Federation investigation as Mr Trump and his staff boarded Air Force One for Saudi Arabia - the first stop on his first foreign trip as President.
Trump has repeatedly slammed the FBI and congressional investigations as a "hoax" and blamed disgruntled officials at intelligence agencies for leaking information related to the probes.
Trump met with the Russians on May 10, the day after he fired Comey.
The Trump administration already was engulfed in crisis as the Justice Department appointed former FBI Director Robert Mueller as special counsel to lead the investigation into Russian election meddling and whether anyone close to Trump colluded in the effort. Rather, White House press secretary Sean Spicer told the Times the pressure Trump was referring to was on his administration's "ability to engage and negotiate with Russian Federation".
Mr Trump has reacted furiously to the appointment, denying he had done anything that might merit prosecution or even impeachment, and then added of the lingering allegations and questions: "I think it's totally ridiculous".
Mr Comey's willingness to testify in an open session will likely alarm the White House, which has been struggling to contain the fallout from the sacking of one of America's highest profile officials.