US President Donald Trump has warned fired FBI chief James Comey against leaking material to the media.

In a tweet on Friday, he said Comey had “better hope that there are no ‘tapes’ of our conversations”.

Comey, who had been leading an inquiry into possible collusion between Trump election campaign officials and Russia, was fired on Tuesday.

Trump said he had been told twice by Comey over dinner and once over the phone that he was not a target of the inquiry.

The president said: “I said: ‘If it’s possible, would you let me know: am I under investigation?’ He said: ‘You are not under investigation.'”

Trump said this week he alone was responsible for the decision to sack Comey, calling him a “showboat” and “grandstander”.

This explanation appeared to undermine earlier comments from administration officials that Comey had been fired on the recommendation of Attorney General Jeff Sessions and his deputy Rod Rosenstein.

The first line of Trump’s letter sacking Comey refers to a memo written by Rosenstein and says: “I have accepted their recommendation”.

In another of his Friday tweets, Trump addressed the differences, saying: “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 added: “Maybe the best thing to do would be to cancel all future “press briefings” and hand out written responses for the sake of accuracy?”

Trump has dismissed the FBI investigation as a “charade” and has said Democrats are using “fake news” about collusion with the Russians as an excuse for losing the election.

In another tweet on Friday, Trump said: “When (former Director of National Intelligence) James Clapper himself, and virtually everyone else with knowledge of the witch hunt, says there is no collusion, when does it end?”

However, Comey’s successor, acting FBI Director Andrew McCabe, said on Thursday that it remained “a highly significant investigation”.

In testimony to the Senate intelligence committee, he also cast doubt on White House claims that Comey had lost the confidence of his staff.

“I can confidently tell you that the vast majority of employees enjoyed a deep and positive connection to Director Comey,” McCabe said.