WASHINGTON ― The Senate Select Committee on Intelligence said Thursday that it has found no evidence to substantiate President Donald Trump’s claim that former President Barack Obama had Trump Tower wiretapped.

“Based on the information available to us, we see no indications that Trump Tower was the subject of surveillance by any element of the United States government either before or after Election Day 2016,” committee Chairman Richard Burr (R-N.C.) and Vice Chairman Mark Warner (D-Va.) said in a statement.

He took Trump’s allegations seriously, Burr told reporters on Wednesday, so he “searched and talked to every federal agency about whether there were any warrants that existed” before reaching a conclusion.

With the statement from the Senate Intelligence Committee chiefs, it’s a bicameral bipartisan assessment that the president accused his predecessor of wiretapping him without any evidence to back up the claim.

House Intelligence Committee Chairman Devin Nunes (R-Calif.), who served on Trump’s transition team, told reporters on Wednesday that if you “take the tweets literally … then clearly the president was wrong.” Trump’s willingness to “make such an accusation without basis,” said Rep. Adam Schiff (D-Calif.), the ranking Democrat on the committee, is a national security concern because it could make the public less likely to trust the president during a time of crisis.

House Speaker Paul Ryan (R-Wis.) said Thursday that “no such wiretap existed,” citing the work done by the congressional intelligence committees.

Earlier this month, Trump fired off a series of early-morning tweets, accusing Obama of wiretapping Trump Tower before the election. The White House insisted for weeks that the Justice Department could provide evidence to support Trump’s claim. After missing a deadline set by Nunes and Schiff, the department asked for more time to review their request and “to determine what if any responsive documents may exist.”

As congressional Republicans distanced themselves from Trump’s tweets, the White House started to walk back the accusation. “The president used the word wiretap in quotes to mean, broadly, surveillance and other activities,” White House press secretary Sean Spicer told reporters on Tuesday.

Trump used this line of argument in an interview with Fox News’ Tucker Carlson on Wednesday night. “When I say wiretapping, those words were in quotes,” he said. “That really covers ― because wiretapping is pretty old-fashioned stuff ― but that really covers surveillance and many other things. And nobody ever talks about the fact that it was in quotes, but that’s a very important thing.”

The Senate Intelligence Committee said in its Thursday statement that it did not find evidence of “surveillance,” using the broader term instead of the more specific “wiretapping.”

Even after the Senate committee’s statement, Spicer insisted Thursday afternoon that the president “stands by” the claim that Obama ordered surveillance of Trump Tower.

In a bizarrely combative White House briefing, Spicer read a series of news reports, citing unnamed sources who said that the FBI is leading a multi-agency investigation into possible ties between Trump associates and the Russian government.

According to several of those reports, the FBI sought (and may have obtained) a warrant from the Foreign Intelligence Surveillance Court to monitor several of Trump’s aides who were suspected of having suspicious communications with Russian intelligence officials. Spicer presented those reports as evidence that Trump’s tweets were correct.

But all of those reports describe the Justice Department seeking out legal ways to pursue its investigation. None allege that Obama, as president, ordered surveillance against Trump ― a move that would have violated longstanding protocols insulating the Justice Department from White House meddling.

This story has been updated with information about Spicer’s Thursday afternoon press briefing.