The US senate intelligence committee has found no evidence to support President Donald Trump's explosive claim that Barack Obama wiretapped him, the committee chair said in a statement.
Richard Burr, the Republican senator for North Carolina who is chairman of the committee, and his Democrat counterpart, Mark Warner, issued a brief statement on Thursday afternoon.
“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,” they said.
Their comments came the day after the top Democrat and Republicans on the house intelligence committee held a press conference, stating that they too had found no evidence to back up Mr Trump's allegation of illegal activity by his predecessor.
The justice department is also doing its own review of whether Mr Trump or any of his associates were the subject of surveillance, and is yet to comment.
But the committees' findings are likely to heap further pressure on Mr Trump to come up with concrete proof for his accusations.
He described Mr Obama as a "bad (or sick)" man, and said that Mr Obama's administration was involved in a political witch hunt, likening it to McCarthyism.
Terrible! Just found out that Obama had my "wires tapped" in Trump Tower just before the victory. Nothing found. This is McCarthyism!— Donald J. Trump (@realDonaldTrump) March 4, 2017
But Mr Trump shows no sign of backing down on his claims.
On Wednesday night he told Fox News that he was confident evidence would be produced.
"I think you're going to find some very interesting items coming to the forefront over the next two weeks," he said.
He also gave some insight into the source of the claims.
"The New York Times wrote about it," he said. "Not that I respect The New York Times. I call it the failing New York Times. But they did write on January 20 using the word wiretap.
"And I think if you watched the Bret Baier (Fox News presenter) and what he was saying and what he was talking about and how he mentioned the word wiretap, you would feel very confident that you could mention the name. He mentioned it. And other people have mentioned it."
The New York Times and Mr Baier reported how communications between some of Mr Trump's aides - Carter Page, Paul Manafort and Roger Stone - and Russian figures had come onto the radar of the intelligence agencies. Russian figures operating in the US know that their communications are routinely listened to by the US authorities.
But the paper and the television channel did not say that Mr Obama ordered the intelligence agencies listen in to Mr Trump's communications.