US lawmakers on Sunday called on President Donald Trump to turn over any tapes of conversations with fired Federal Bureau of Investigation chief James Comey, even 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 FBI director against talking to the media.
Trump and the White House declined to confirm or deny whether such tapes exist.
Republican Senator Lindsey Graham of South Carolina said the White House must "clear the air" about whether there are any taped conversations.
"You can't be cute about tapes. If there are any tapes of this conversation, they need to be turned over," Graham told NBC's "Meet the Press" programme.
Trump sparked a political firestorm when he abruptly fired Comey last week. The FBI under Comey has been investigating alleged Russian meddling in the US election and possible ties between Moscow and the Trump campaign.
Democrats have accused Trump of attempting to thwart the FBI's probe and have called for some type of independent inquiry into the matter.
Trump has said he removed Comey because he was not doing a good job and that Comey had lost the support of FBI employees.
Trump tweeted on Friday that "James Comey better hope that there are no 'tapes' of our conversations before he starts leaking to the press!"
'Release the tapes'
If there are recordings, Republican Senator Mike Lee of Utah told Fox News, it was "inevitable" that they would be subpoenaed and the White House would have to release them.
Lee, who was on Trump's list of potential replacements for Supreme Court Justice Antonin Scalia, also said recording conversations in the White House is "not necessarily the best idea".
Meanwhile, Trump's threat about tapes has intensified calls from Democrats for an independent probe of alleged Russian meddling in the 2016 US election.
Senate Democratic Leader Chuck Schumer said Trump must immediately provide Congress with any tapes and warned that destroying existing tapes would violate the law.
Schumer also said Senate Democrats are weighing whether to refuse to vote on a new FBI director until a special prosecutor is named to investigate Trump's potential ties to Russia.
"To have that special prosecutor, people would breathe a sigh of relief because then there would be a real independent person overlooking the FBI director," Schumer told CNN'.
Trump has continued to question whether it was behind the hacking of email accounts belonging to Democrats involved in Hillary Clinton's 2016 presidential campaign.
But Secretary of State Rex Tillerson told NBC there is no question that "the Russians were playing around in our electoral processes".
He defended Trump's decision to meet with Russian Foreign Minister Sergei Lavrov in the Oval Office last week.
"It's in the interest of the American people, it's in the interest of Russia and the rest of the world that we do something to see if we cannot improve the relationship between the two greatest nuclear powers in the world," Tillerson said.
Meanwhile, the Justice Department began interviewing candidates for the FBI director job on Saturday. People under consideration include acting FBI Director Andrew McCabe, Republican Senator John Cornyn of Texas, New York Appeals Court Judge Michael Garcia and former Assistant Attorney General Alice Fisher, reports Reuters citing a White House official.
Meanwhile, a NBC / Wall Street Journal poll released on Sunday found that 29 per cent of Americans approve of Trump's decision to fire Comey, while 38 per cent disapprove.
If a Senate vote on a new FBI director breaks down along party lines, Democrats would not have the votes to block a nominee because Republicans hold a majority in the chamber.
"The key is getting some of our Republican colleagues to join us," Schumer said.