Counselor to the President Kellyanne Conway challenged FBI director James Comey to speak out publicly following reports he asked the Justice Department to deny US President Donald Trump's claims that former president Barack Obama wiretapped him.

"If Mr Comey has something he'd like to say, I'm sure we're all willing to hear it," Conway told Fox News' Jeanine Pirro in an interview on Justice with Judge Jeanine late Sunday 5 March.

"I don't know what Mr Comey knows," Conway said. "All I saw was a published news report. I didn't see a statement from him," she added, urging that "if he knows" something "of course he can issue a statement."

Earlier in the day The New York Times cited senior American officials who said Comey is arguing that the Department of Justice (DOJ) must correct Trump's claims because they falsely suggests the FBI broke the law by wiretapping an American without a warrant.

On Saturday Trump tweeted that he "just found out that Obama had my 'wires tapped' in Trump Tower just before the victory. Nothing found. This is McCarthyism!"

In another tweet the president said "President Obama was tapping my phones in October" and indicated that a request for a warrant had been "turned down by court earlier". The president has not produced evidence to back up his claim, but called for an investigation.

White House press secretary Sean Spicer said there would be no further comment until the investigations are completed.

A special Foreign Intelligence Surveillance Act (Fisa) warrant would have been needed to wiretap Trump. In an interview on NBC's Meet the Press early on Sunday the former director of national intelligence under President Barack Obama, James Clapper, denied that a warrant was issued to tap candidate Trump's phones.

A US official confirmed to The Associated Press on Sunday that the FBI has asked the Justice Department to dispute Trump's claim. The Justice Department has yet to dispute the allegations publicly.

Last week Attorney General Jeff Sessions – who was a senior adviser to Trump during the 2016 election – recused himself from an ongoing DOJ investigation in collaboration with other law enforcement and intelligence agencies. They were pursuing leads from informants and foreign communications intercepts about the Trump campaign's contacts and Russian intelligence officers before the November election.

Both Reuters and the New York Times have confirmed that US intelligence agencies have intercepted communications between members and associates of the Trump campaign and Russian intelligence-linked officials. No details of the content of those calls or examples of anywrongdoing have been made public.

Several Trump administration officials and associates have denied contacts with the Russian government only to be revealed later in news reports to have had those contacts.

"We know there were politically motivated stories and investigations all through the campaign season, and those come from credible news sources, and the president wants to get to the bottom of that," said Conway on Fox. "If you're going to continue to investigate Russiagate, Russia, Russia, Russia. Why not add [Trump's] investigation these allegations?"