House Intelligence Committee Chairman Rep. Devin Nunes, R-Calif., right, accompanied by the committee's ranking member, Rep. Adam Schiff, D-Calif., talks to reporters, on Capitol Hill in Washington, Wednesday, March, 15, 2017, about their investigation of Russian influence on the American presidential election. Both lawmakers said they have no evidence to back up President Trump's claim that former President Barack Obama wiretapped Trump Plaza during the 2016 campaign. (AP Photo/J. Scott Applewhite)
House Intelligence Committee Chairman Rep. Devin Nunes, R-Calif., right, and Rep. Adam Schiff, D-Calif., talk to reporters in Washington Wednesday about their investigation of Russian influence on the American presidential election. (J. SCOTT APPLEWHITE/AP)
The chairman of the House intelligence committee said Wednesday that the panel has found no evidence to substantiate President Donald Trump's claim his campaign headquarters was wiretapped on orders from President Barack Obama.
"We don't have any evidence that that took place," Rep. Devin Nunes, R-Calif., said in a press conference on Capitol Hill. "I don't believe, just in the last week of time, the people we've talked to, I don't believe there was an actual tap of Trump Tower."
The congressional committee, one of multiple looking into Russia's attempts to interfere in last year's presidential election, is holding its first hearing as part of its probe on Monday, and has asked the Justice Department to turn over any materials that might support the supposition that U.S. intelligence operatives were listening in on conversations held by Trump campaign associates.
Nunes said last week that "at this point we don't have any evidence" to support the president's tweeted claim that "Obama had [his] 'wires tapped' in Trump Tower just before the victory," but he promised to investigate.
"We still want the Justice Department to respond to our letter," the committee's top Democrat, Rep. Adam Schiff of California, said at Wednesday's press conference. "We've given them until March 20, we're both willing to use compulsory process if that's necessary, though neither of us, I think, believe that will be necessary."
The two lawmakers also announced they had sent a new request to Adm. Mike Rogers, director of the National Security Agency, FBI Director James Comey and CIA Director Mike Pompeo demanding the agencies turn over a list of U.S. persons affiliated with Trump or Democratic rival Hillary Clinton who, in the course of regular monitoring of foreign agents, may have been recorded and had their identities "unmasked" and disseminated as part of a government request.
Nunes expressed concern that retired Gen. Michael Flynn – who resigned as Trump's national security adviser in the wake of revelations that he had spoken to Russian Ambassador Sergey Kislyak about U.S. sanctions ahead of Trump taking office – was not the only American whose identity had been "unmasked" and potentially leaked to the press.
"I remain even more concerned about … the incidental collection of Americans that were possibly tied to the Trump campaign that could have been leaked, similar to Gen. Flynn, and secondly, the unmasking of Americans' names, potentially for political purposes," Nunes said. "We're continuing to ask more about that."
Rogers and Comey are both set to testify at Monday's hearing, Nunes said Wednesday. Former CIA Director John Brennan, former Director of National Intelligence James Clapper and former acting Attorney General Sally Yates are due to testify at a hearing a week later.
It's not clear whether intelligence officials have evidence of any additional conversations between Trump campaign associates and Russian officials, but Nunes said "it's possible" others could have been swept up in intelligence collection, including Trump.
"We should know that by Friday," he said.
Nunes and Schiff also indicated they would be willing to issue a subpoena for the names they're seeking if the intelligence and law enforcement agencies fail to respond by the Friday deadline.
Meanwhile, Schiff said there is "no daylight between [he and Nunes] on the fact that neither one of us have seen any evidence to support" Trump's tweeted accusation that Obama ordered the wiretapping of Trump Tower. He also criticized both the president and White House press secretary Sean Spicer over the allegations.
"You can't level an accusation of that type without either retracting it or explaining just why it was done," Schiff said. "There are, from a national security perspective, great concerns if the president is willing to state things like that without any basis, because the country needs to be able to rely on him, particularly if we have a crisis that is an external crisis, as every president does within their term of office."
Spicer, he said, has provided contradictory information to the public.
"Mr. Spicer has represented that he is not aware of any investigation that was targeting the president, and presumably no court-ordered surveillance of the president. He has also said that he is confident that the president was speaking accurately when he said he was wiretapped by his predecessor," Schiff said. "Those two things cannot both be true unless he is suggesting that the FBI was engaged in a rogue operation ... [and] there is absolutely no evidence of that, and no suggestion of any evidence of that.
"To even put that forth was irresponsible of the president and his spokesman," Schiff said.
Elsewhere in Congress, Sen. Lindsey Graham, R-S.C., threatened to pursue a subpoena if he doesn't get a reply from Comey by Wednesday on a request for "any warrant applications and court orders" that would back up Trump's claims he was wiretapped.
"He hasn't answered that letter," Graham, who chairs the Senate Judiciary Committee's Subcommittee on Crime and Terrorism, told Fox News on Wednesday. "If he doesn't answer it today, I'm going to the chairman of the committee, Sen. [Chuck] Grassley, and seek his support to subpoena."
Updated on March 15, 2017: This article has been updated.