During his Fox News appearance, Nunes said he has seen no evidence of collusion between Trump associates and the Russians during the election.
Comey will address his agency's investigation into the Trump campaign's contacts with Russian Federation.
Representative Devin Nunes, chairman of the House Intelligence Committee, said Friday that the Justice Department had "fully complied" with the panel's request for any materials related to Trump's wiretapping claim. But no credible evidence has emerged to support those claims, and the top Republican and Democrat on the Senate Intelligence Committee said last week that they have seen nothing that supports the allegation.
Monday's hearing features testimony from FBI Director James Comey, who has asked the Justice Department to publicly rebuke Trump's claims against Obama.
Several congressional panels have launched investigations into Russia's alleged interference, including House and Senate intelligence committees, which have jurisdiction over the nation's 17 intelligence agencies, and the House and Senate judiciary committees.
Making reference to a colleague's claim that the legislative branch needs to "get to the bottom" of Trump's allegations, Schiff said: 'We are at the bottom of this'.
'It never hurts to say you're sorry, ' Hurd, a former undercover Central Intelligence Agency operative, told ABC's George Stephanopoulos.
"It's a bit garbled in the video but he didn't mean to say there is one person under surveillance, he's saying there is no one under surveillance, which is why he says "at all" at the end of the sentence", the spokesman said.
The president's choice for national security adviser, Michael Flynn, was forced to resign in February after it was revealed he had talked with Sergey Kislyak, Russia's ambassador to the USA, during the presidential transition and then misled Vice President Mike Pence by denying they discussed the possible easing of us sanctions.
"What the president said was just patently false, and the wrecking ball it created now has banged into our British allies and our Germany allies", Schiff claimed.
In recent weeks, Trump joined the fray with counter-accusations of his own, such as his unfounded charge that the Obama administration conducted a wiretap of his phones at Trump Tower in NY. Asked about the flap, Trump said: "That was a statement made by a very talented lawyer on Fox, and so you shouldn't be talking to me, you should be talking to Fox. OK?" "There's certainly enough for us to conduct an investigation". As Sen. John McCain, R-Ariz., said a month ago: "All of us know that leaks happen in this town, and we all don't like it - but the fact is that you now have a much larger issue to address".
"I don't know the basis for President Trump's assertion", US Senator Susan Collins, a Republican, said on NBC's Meet the Press on Sunday.
"I think it would be quite good for the administration to put forward what evidence there is", Cruz told CBS television. While Trump used the term "wiretapping", he and his aides say that now refers to "surveillance" in general. Since then, Trump has said he was speaking more generally about possible surveillance methods besides wiretaps.
Both the House and Senate intelligence committees are now looking into the possibility of Russian interference during the election.
United States intelligence agencies have accused Moscow of hacking computer systems belonging to Hillary Clinton's Democratic Party, among other methods. I was the dude in the back alleys at 4 in the morning collecting intelligence to protect our homeland.
The frequency and the level of those contacts raised alarms in USA intelligence and law enforcement circles.
"At the outset of the investigation, there was circumstantial evidence of collusion. And I do believe he owes us that explanation". "This is not going away until we find out whether these are coincidences or a convergence".