Asked on Friday if he would be willing to go under oath to give his version of his interactions with Comey, Trump replied, “100%”.

He said he would be happy to speak to special counsel Robert Mueller, who is investigating allegations that Russia interfered with the election and colluded with Trump’s campaign.

“I would be glad to tell him exactly what I just told you,” Trump told a reporter.

Trump’s offer to testify under oath would pit his word against Comey’s before federal investigators.

If either Trump’s testimony or memos written by Comey about his conversations with the president turn out to be untrue, either man could be charged with lying to federal investigators.

A US president is given a wide array of immunities from criminal prosecutions. The US constitution does not directly address whether the president can be criminally prosecuted, and the area is the subject of legal debate. A president can be charged after leaving office.

Trump wrote earlier on Friday on Twitter that the former FBI head had vindicated him by telling the Senate Intelligence Committee that the president had not been personally under investigation in the Russia probe.

With a single tweet, Trump also castigated Comey as “a leaker” for giving an account of his conversation with the president to a law professor who shared it with a news outlet.

“Despite so many false statements and lies, total and complete vindication … and WOW, Comey is a leaker!” Trump tweeted.