US President Donald Trump has warned former FBI director James Comey against leaking to the media, saying he had “better hope that there are no tapes” of their conversations.

In a series of tweets, Mr Trump threatened Mr Comey and also warned that he may cancel all White House press briefings.

“James Comey better hope that there are no ‘tapes’ of our conversations before he starts leaking to the press!” he tweeted.

CNN, citing an unnamed source, reported Comey is “not worried about any tapes”.

James Comey better hope that there are no "tapes" of our conversations before he starts leaking to the press!

— Donald J. Trump (@realDonaldTrump) May 12, 2017

Late on Friday White House press secretary Sean Spicer repeatedly refused to address whether recording devices had been placed in the White House.

He dismissed the notion that the President threatened the former FBI director.

“The President has nothing further to add on that,” Mr Spicer said when questioned about a recording system.

“The tweet speaks for itself.”

The President’s abrupt move to fire the director of the FBI during an ongoing investigation into whether his presidential campaign had ties to Russia stunned Washington, and was swiftly condemned by Democrats and some in his own party.

Even before Mr Trump’s provocative tweet, the White House was scrambling to clarify why Mr Comey was fired.

Mr Trump told NBC he had planned to fire Mr Comey all along, regardless of whether top Justice Department officials recommended the stunning step.

The White House initially cited a Justice Department memo criticising Mr Comey’s handling of last year’s investigation into Hillary Clinton’s emails as the impetus for Mr Trump’s decision.

But Mr Trump on Thursday acknowledged for the first time the Russia investigation, which he dismissed as a “made-up story”, was also on his mind as he ousted the man overseeing the probe.

He later tweeted that no one should expect his White House to give completely accurate information.

As a very active President with lots of things happening, it is not possible for my surrogates to stand at podium with perfect accuracy!….

— Donald J. Trump (@realDonaldTrump) May 12, 2017

“As a very active President with lots of things happening, it is not possible for my surrogates to stand at podium with perfect accuracy!” he said.

White House spokeswoman Sarah Huckabee Sanders insisted the information she and her colleagues offered was consistent.

“It was a quick-moving process,” she said.

“We took the information we had as best we have it and got it out to the American people as quickly as we could.”

In his termination letter to Mr Comey, Mr Trump said the firing was necessary to restore “public trust and confidence in the FBI”.

“While I greatly appreciate you informing me, on three separate occasions, that I am not under investigation, I nevertheless concur with the judgment of the Department of Justice that you are not able to effectively lead the bureau,” Mr Trump said in the letter dated Tuesday.

Mr Comey has not commented since he was fired but associates of his said they believed any tapes would validate Mr Comey’s side of the story.

– with AAP