The Comey firing also drew red flags from Republicans in the House of Representatives, as Oversight Committee chairman Rep. Jason Chaffetz (R-UT) asked the Inspector General of the Justice Department to review the President's decision to oust Comey.
He refused to comment on what Comey did or didn't say, but when asked whether it would be common for an FBI director to notify someone they were not the target of an investigation, said "I'm not aware of that being a standard practice".
In addition to contradicting the official White House timeline, Trump also called Comey a "showboat" and a "grandstander".
On Wednesday, the White House added that Trump had been thinking about letting Comey go since the election in November and became "strongly inclined" after Comey's most recent congressional testimony.
Congressman Adam Schiff, the top Democrat on the House Intelligence Committee, said he did not see the firing of FBI Director James Comey coming. "He said, 'You are not under investigation'". "Me, personally. I'm not talking about campaigns, I'm not talking about anything else". "Very simply. He was not doing a good job", Trump said upon being asked why he had suddenly booted the Federal Bureau of Investigation chief on Tuesday.
In a statement, Grassley said that Comey had previously briefed him and the panel's top Democrat, Senator Dianne Feinstein, and that the lawmakers "heard nothing that contradicted the president's statement".
Mr Trump is the first president since Richard Nixon to fire a law enforcement official overseeing an investigation with ties to the White House.
U.S. presidents are normally at pains to avoid any suggestion of interference or even commenting on ongoing investigations.
Republican Senate Majority Leader Mitch McConnell told Democrats not to get their hopes up.
Trump was ready to fire Comey from the start.
"I can't comment on any conversations the director may have had with the president", McCabe said.
The Trump administration has said Comey's firing was unrelated to the Russian Federation investigation.
By around noon, however, the action had moved away from the public hearing, as Deputy Attorney General Rod Rosenstein - who wrote the letter criticizing Comey that the White House cited in the firing - arrived on Capitol Hill to meet with senators in private.
"I mean, really?!" the reporter shot back.
"I actually asked him", Trump recalled.
It comes just as the FBI appeared to be ramping up its investigation of Trump associates' ties to Russian Federation. "Regardless of the recommendation, I was going to fire Comey". General Vincent Steward testified about global threats before the Senate intelligence committee on Thursday, May 11, 2017.
"We do not typically answer that question", said McCabe.
Trump pointedly noted he was not refering to his campaign.