Washington, DC: US politicians are calling on President Donald Trump to turn over any tapes of conversations with fired FBI chief James Comey, potentially setting up a showdown with the White House as Democrats considered a boycott of the vote on Comey's replacement.

In a highly unusual move, Trump last week appeared to suggest on Twitter that he might have tapes of conversations with Comey and warned the former director of the Federal Bureau of Investigation against talking to the media.

Trump and a White House spokesman declined to confirm or deny whether such tapes exist.

Trump claims he removed Comey because he was not doing a good job and that Comey had lost the support of FBI employees.