In a press conference Wednesday morning on Capitol Hill, representatives Devin Nunes (R-Ca.) and Adam Schiff (D-Ca.) announced that there is no evidence supporting President Donald Trump’s claim that Trump Tower was wiretapped during his presidential campaign.

“That evidence still remains the same,” Nunes said, “that we don’t have any evidence that that took place, and I don’t believe there was an actual wiretap of Trump Tower.

“It deeply concerns me that the president would make such an accusation without basis,” Schiff said.

Nunes and Schiff, who lead the House Intelligence Committee and have overseen the bipartisan investigation into Russian influence in the 2016 election, have made repeat requests to the executive branch for evidence of an illegal wiretap. The White House was given a deadline of Monday to provide such evidence, which it did not meet. The administration instead shifted its narrative to discuss illegal wiretaps in general.

“When you begin an investigation, you don’t begin by stating what you believe to be the conclusion,” Schiff said on Monday.

The controversy began after Trump posted a series of tweets on Mar. 4 accusing former president Barack Obama of tapping Trump Tower during the campaign.

“President Obama wouldn’t physically go over and wiretap Trump Tower, so you have to decide, are you going to take the tweets literally?” Nunes added. “And if you are, the president was wrong.”

Although a FISA warrant was issued against Trump Tower in October, the details and specific target(s) of this warrant have not been made public. While the conversations of former National Security Advisor Michael Flynn were intercepted, no evidence to date has been brought forth of any other individual being wiretapped.

Nunes expressed concern about the “incidental collection of Americans that were possibly tied to the Trump campaign that could have been leaked, similar to General Flynn, and similarly the unmasking of Americans’ names for political purposes.” He later added that if Flynn’s conversations had been incidentally intercepted, it was “very possible” that other conversations, including those of the president, were also caught up, “if he was speaking with individuals under surveillance.”

Nunes and Schiff said they would follow up with FBI Director James Comey and CIA Director Michael Pompeo for specific evidence of American citizens caught up in this warrant.

Comey is scheduled to testify publicly for the first time about the Russia investigation on Monday.