White House spokesman Sean Spicer said he was almost certain President Donald Trump had not spoken to FBI Director James Comey about Mr Trump’s claim, without evidence, that the previous administration wiretapped him during the 2016 campaign.
Mr Spicer told reporters he was "almost 100% certain" Mr Trump had not spoken to Mr Comey since the president claimed on Twitter on Saturday that former President Barack Obama ordered a wiretap at Trump Tower in New York.
Mr Comey has asked the Justice Department to reject that claim.
The New York Times, citing senior US officials, first reported that Mr Comey believes Mr Trump's unsubstantiated claim about his predecessor to be false.
The department has not made any statement.
Mr Comey made the request on Saturday because "there is no evidence to support it, and it insinuates that the FBI broke the law," the paper reported the officials as saying.
Questioning the president's truthfulness, Mr Comey's extraordinary measure provides an indication of the implications of the uncharted territory Mr Trump has entered with his accusation.
However, although the Justice Department, which is headed by Attorney General Jeff Sessions, a staunch Trump supporter, oversees the FBI, it is not clear why Mr Comey did not issue a statement himself.
Mr Trump wants Congress to investigate the leaking of classified information, as well as the allegations over wiretapping.
Mr Spicer said he had spoken to Mr Trump about the issue and the president had indicated he would like to see Congress broaden the scope of ongoing investigations into Russia's influence over the US election to include both elements.
Mr Trump made his claim in a series of tweets on Saturday.
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) 4 March 2017
He provided no evidence to back up the claim.
Mr Obama denied the allegation via a spokesman as "simply false".
However, the Republican chair of the House Permanent Select Committee on Intelligence, Devin Nunes, said his panel would look into Mr Trump's claim after the White House yesterday urged Congress to investigate his allegation.
The accusation has prompted a firestorm of criticism, with many saying Mr Trump's incendiary claim was aimed at diverting attention from a series of revelations about his aides' meetings with Russian officials.
Republicans unveil plan to repeal, replace Obamacare
US House Republicans unveiled long-awaited legislation that would repeal and replace the health care reforms known as Obamacare, largely under the framework that President Donald Trump laid out in his recent congressional address.
The American Health Care Act would dismantle several of the core aspects of the reforms, including ending subsidies and taxes, as well as rules requiring individuals to have insurance.
"After years of Obamacare's broken promises, House Republicans today took an important step," House Energy and Commerce Committee Chairman Greg Walden said in a statement.
"Simply put, we have a Better Way to deliver solutions that put patients - not bureaucrats - first, and we are moving forward united in our efforts to rescue the American people from the mess Obamacare has created."
The new bill, which requires passage by the House of Representatives and the Senate, preserves two popular elements of Obamacare: prohibiting health insurers from denying coverage to people with pre-existing conditions, and allowing dependents to remain on their parents' plans until age 26.
