The FBI director James Comey has asked the Justice Department to publicly reject President Trump’s claim that Obama ordered the tapping of Mr Trump’s phones, according to US media.
Mr Comey has argued that the allegation is false and must be corrected, senior officials told the Washington Post, but the department has not released a statement.
According to the newspaper, Mr Comey and the Justice Department have been working to reject the claim because it falsely insinuates that the FBI broke the law.
Trump made the claims on Saturday morning - and they have been emphatically denied by Mr Obama's team.
Posting on Twitter, Mr Trump said it marked a “new low” that could be the biggest political scandal since Watergate.
The claims - for which Mr Trump offered no evidence - have caused a political uproar in the US.
A spokesman for President Obama said the allegations were “simply false”.
Under US law, presidents cannot order the surveillance of private citizens.
The then director of National Intelligence, James Clapper, has denied such an order existed.
He told NBC, he would have known about a "Fisa court order on something like this".
Donald Trump has asked the US Congress to examine whether the Obama administration abused its executive "investigative authority", during the 2016 presidential election campaign.
White House press Secretary Sean Spicer said Mr Trump had asked for the investigation to be part of an ongoing probe into Russia's alleged interference in the election