US President Donald Trump has turned to Congress for help finding evidence to support his unsubstantiated claim that former President Barack Obama had Trump's telephones tapped during the election.
Mr Obama's intelligence chief says no such action was ever carried out.
Republican leaders of Congress appeared willing to honour the President's request, but the move has potential risks for the President, particularly if the House and Senate intelligence committees unearth damaging information about Mr Trump, his aides or his associates.
Mr Trump claimed in a series of tweets without evidence on Saturday that his predecessor had tried to undermine him by tapping the telephones at Trump Tower, the New York skyscraper where Trump based his campaign and transition operations, and maintains a home.
Mr Obama's director of national intelligence, James Clapper, said nothing matching Mr Trump's claims had taken place.
"Absolutely, I can deny it," said Mr Clapper, who left government when Mr Trump took office in January. Other representatives for the former president also denied Mr Trump's allegation.
The New York Times reported that FBI director James Comey has asked the Justice Department to publicly reject Mr Trump's assertion.
The Times reported senior American officials say Mr Comey argued that the claim must be corrected because it falsely insinuates that the FBI broke the law.
No such statement has been issued by the Justice Department.
White House press secretary Sean Spicer said without elaborating that Mr Trump's instruction to Congress was based on "very troubling" reports "concerning potentially politically motivated investigations immediately ahead of the 2016 election."
Mr Spicer did not respond to inquiries about the reports he cited in announcing the request.
Mr Spicer said the White House wants the congressional committees to "exercise their oversight authority to determine whether executive branch investigative powers were abused in 2016."
He said there would be no further comment until the investigations are completed, a statement that House Democratic leader Nancy Pelosi likened to autocratic behaviour.
"It's called a wrap-up smear. You make up something. Then you have the press write about it. And then you say, everybody is writing about this charge. It's a tool of an authoritarian," Mr Pelosi said.
Mr Spicer's chief deputy, Sarah Huckabee Sanders, said she thinks Mr Trump is "going off of information that he's seen that has led him to believe that this is a very real potential".