Fake news - provided, no doubt, via a fake leak:

WASHINGTON — President Trump told Russian officials in the Oval Office this month that firing the F.B.I. director, James B. Comey, had relieved “great pressure” on him, according to a document summarizing the meeting.

“I just fired the head of the F.B.I. He was crazy, a real nut job,” Mr. Trump said, according to the document, which was read to The New York Times by an American official. “I faced great pressure because of Russia. That’s taken off.”

;)
https://www.nytimes.com/2017/05/19/us/politics/trump-russia-comey.html