The late January dinner was arranged at Trump's request, the source added.

White House press secretary Sean Spicer on Friday rejected the idea that Trump asked Comey to pledge his loyalty. "I think the President wants loyalty to his country and to the rule of law," Spicer said.

Trump himself echoed those remarks in an interview with Jeanine Pirro on Fox News on Friday.

Pressed by Pirro on whether he asked Comey for his loyalty, Trump responded: "No, I didn't, but I don't think it would be a bad question to ask. I think loyalty to the country, loyalty to the US, is important. You know, it depends on how you define loyalty, No. 1; No. 2, I don't know how it got out there because I didn't ask that question."

A description of the dinner and conversation was first reported Thursday night by The New York Times, although CNN had previously reported Comey's refusal to give Trump any assurance of personal loyalty.

Asked on MSNBC Friday about the dinner, former Director of National Intelligence James Clapper said Comey "was uneasy with it, just for the appearance."

As CNN reported, Comey's refusal to pledge loyalty is one of the reasons the President fired him, the other being the acceleration of the probe into alleged collusion between Trump's presidential campaign and Russia.

The initial, official White House version of how and why Comey was fired was that Deputy Attorney General Rod Rosenstein , fresh on the job, wrote a memo expressing concern about the way Comey had handled the Hillary Clinton email investigation.

But mounting evidence suggests Comey was actually fired because of the Russian investigation.

In the initial version of the timeline, Trump acted on Rosenstein's advice after the memo was sent this week. But sources have told CNN that Trump's decision to ax Comey was made after he grew increasingly frustrated with him following a congressional hearing last week in which he said he was "mildly nauseous" over the idea that he helped sway the 2016 election.

On Thursday, Trump threw two days of official White House accounts into dispute by insisting he'd long planned to fire Comey, even before his Justice Department provided him with a reason, and suggesting he was thinking about the FBI's Russia investigation when he made the decision.

"When I decided to just do it, I said to myself, I said 'You know, this Russia thing with Trump and Russia is a made-up story, it's an excuse by the Democrats for having lost an election that they should have won,' " Trump told NBC.

"Regardless of the recommendation," Trump told NBC, "I was going to fire Comey."

That flew in the face of what his top deputies -- including Vice President Mike Pence -- had said publicly about the incident in the 24 hours after the dismissal. Pence said seven times on Capitol Hill Wednesday that Trump acted only after receiving the recommendation to fire Comey from Rosenstein.

Trump issued a thinly veiled threat to Comey Friday morning, appearing to suggest there are possibly recorded conversations between Trump and Comey that could be leaked to counter the former FBI director if necessary.

"James Comey better hope that there are no 'tapes' of our conversations before he starts leaking to the press," Trump tweeted.