That tweet has prompted repeated demands from the congressional committees investigating any possible collusion between Trump's team and Russian Federation during the 2016 campaign, and the process by which he fired Comey, for him to hand over any tapes that exist.
Though Trump has lambasted Comey as a "leaker", he also claimed "total and complete vindication" following the ex-FBI chief's testimony, focusing on Comey's confirmation that Trump was not personally being probed.
Mr Trump also said he never asked Mr Comey for a pledge of loyalty.
When asked by a reporter if Trump asked Comey to drop the investigation into Flynn, he said: "I didn't say that".
"Lordy, I hope there are tapes", Comey told the panel Thursday, emphasizing his belief that the president asked him to shut down the investigation.
Marc Kasowitz said on Thursday that the president never sought to impede the investigation into possible Russian interference in the United States election and that Mr Comey's leaks should be investigated.
Trump also denied asking Comey for a pledge of loyalty during one of a string of private meetings.
Asked what would happen if the tapes turned out to be real and Trump did not give them up, Collins responded, "I would be fine with issuing a subpoena, but that most likely would come from the special counsel's office". Legal experts and pundits say that, along with the firing of Comey itself, could amount to obstruction of justice. I'm not going to say I want you to pledge allegiance. Such an offence potentially could lead to Trump being impeached by Congress, although his fellow Republicans who control the Senate and House of Representatives have shown little appetite for such a move. That was an excuse by the Democrats who lost an election that some people think they shouldn't have lost, because it's nearly impossible for the Democrats to lose the Electoral College, as you know.