The top Democrat on the House Intelligence Committee told CNN Friday that, after meeting with the FBI director, he has not "seen any evidence" to back Trump's claims that he was wiretapped by the Obama administration during the campaign.
"I think when (press secretary) Sean Spicer isn't even willing to talk about it, you know there's a real problem," said Rep. Adam Schiff, who was in a meeting with FBI Director James Comey Thursday night.
Asked if Comey is prepared to talk about the issue at a March 20 hearing before the committee, Schiff replied, "he certainly is prepared for the question, and I don't see any reason why he wouldn't answer it. He might even welcome the opportunity."
Rep. Devin Nunes, the GOP chairman of the committee, said that his panel has sent letters to "multiple agencies" to obtain records by next week ahead of the March 20 hearing. And he said that he still stands by his assertion from earlier this week that he has yet to see evidence confirming Trump's Saturday morning tweet that then-President Barack Obama ordered wiretaps to spy on him during the presidential campaign.
"I'll let my comments stand from the other day, which I still think are the same," Nunes told CNN. "We are very interested in looking into anything to do with (the Foreign Intelligence Surveillance Act) -- especially FISA on any Americans."
He later reiterated that his views are the same from Tuesday when he said that "I have not seen that evidence" when asked at the time if there is any data to back up Trump's wiretapping accusation.
Schiff, a California Democrat, noted that it is still early in the investigation. On Thursday, he said the investigation into Trump's unverified allegations would be public.
"I think what Sean Spicer and the President wanted was to take this spurious claim and try to bury it in a closed hearing in the intelligence committee. We're not going to allow that to happen. We're going to air this very publicly," he told CNN's Chris Cuomo on "New Day."
The Trump administration has so far declined to provide any information about the President's allegations since he tweeted them Saturday. Obama's former aides have emphatically denied Trump's claims, and sources told CNN Obama himself was exasperated after learning of the accusations.
"Nothing has changed," Spicer told CNN's Jim Acosta Wednesday when asked whether there was new evidence to support the claims. "It's not a question of new proof or less proof or whatever. The answer is the same, which is that, I think, there was a concern about what happened in the 2016 election."
The White House spokesman said the intelligence committees have the capabilities to look into the issue objectively.
Schiff said Thursday that Trump will be "exposed" publicly if an investigation reveals that there is no merit to his claims. The intelligence committee already planned to investigate the relationship between Trump associates and Russian officials during the 2016 election.
"If the President is going to make outlandish claims like this in the future, he needs to know he will be exposed and high-ranking people within the US government -- like the director of our intelligence agencies and the FBI -- will be forced to say the President wasn't telling the truth," he said.
Trump making accusations without providing evidence is harmful to democracy and will continue if he is not challenged.
"If we don't confront him on this, you can expect he's going to make other equally false claims in the future and this is not only hurting him but it's hurting the presidency," Schiff said earlier. "It's hurting our credibility around the world."
"I think there are profound questions about whether this President is capable of growing with the job," he added.
This story has been updated to reflect breaking news.