Federal Bureau of Investigation director James Comey to testify on President Trump's unproven wiretap claim

National Security Agency director Mike Rogers will also be testifying.

Todd also asked Collins about the president's explosive, yet still unverified claim that President Obama ordered a wiretap of his phones at Trump Tower during the election.

During his Fox News appearance, Nunes said he has seen no evidence of collusion between Trump associates and the Russians during the election.

On Friday evening, Nunes also issued a statement saying the committee had received information it requested from the Federal Bureau of Investigation on "possible surveillance related to Donald Trump or his associates".

"I don't know the basis for President Trump's assertion".

Whether or not Congressional committees find evidence of surveillance of the Trump campaign or of Russian influence they are determined to track down the source of newspaper reports of undisclosed contact between former national security adviser Michael Flynn and Mr Kislyak, described by United States intelligence sources as a spy recruiter.

"I am concerned that this hearing will not be quite as instructive as a lot of us and a lot of Americans would want because so much of the information lives in a classified world", Himes said.

Sen. Tom Cotton on Sunday previewed the upcoming House hearing, saying Comey's testimony would address "unsubstantiated allegations" of dealings between Moscow and President Donald Trump's campaign.

"There is certainly enough for us to conduct an investigation", Schiff said.

Officials have said they've been unable to find any evidence thus far that Obama had Trump Tower wiretapped. White House Press Secretary Sean Spicer nevertheless included the broadcast in a list of reports he read off in a news conference that purportedly support the president's claim that Obama spied on him.

"There's even been stories written about it in numerous newspapers talking about how they said they left breadcrumbs around to hurt the Trump administration", Nunes said. "The one crime we know that's been committed is that one, the leaking of someone's name", Nunes said.

FBI Director James Comey will also testify on Monday before the House Intelligence Committee in the first public hearing regarding possible Russian interference in the 2016 election. "If the president has evidence of that, I would encourage him to turn it over to the House and Senate intelligence committee", she said.

He answered, "I'll give you a very simple answer. No".

The wiretapping claim was revived Friday, when Trump refused to back down from the claim, citing a Fox News analyst's contention that GCHQ, the British electronic intelligence agency, had helped Obama wiretap Trump.

"I think people need to understand we are in a global war of ideas", Schiff said.

He added: "It's continuing to grow in terms of damage and he needs to put an end to this".

Trump has been dogged by allegations that his associates had ties to Russian officials.

Republicans, meanwhile, will seek to reconstruct the original hack of the Democratic National Committee previous year and ferret out the source of a series of media leaks like the one linked to Flynn.

  • Zachary Reyes