The executive branch has been asked to present any evidence that US President Donald Trump's phone was wiretapped during the election.
The request was made by the House Intelligence Committee, which gave the executive branch until Monday (13 March) to submit the evidence, an anonymous senior aide told the Associated Press.
Democrat Adam Schiff who sits on the panel told AP: "We should be able to determine in fairly short order whether this allegation is true or false."
The accusation emerged in a series of tweets made on Saturday (3 March).
Trump wrote: "How low has President Obama gone to tapp my phones during the very sacred election process. This is Nixon/Watergate. Bad (or sick) guy!
"I'd bet a good lawyer could make a great case out of the fact that President Obama was tapping my phones in October, just prior to Election!"
A spokesperson for Obama denied the claims, which Trump has so far not backed up with any evidence.
Other lawmakers – including some within the GOP – have also requested evidence of any wiretapping, with South Carolina Senator Lindsey Graham previously stating he was ready to subpoena intelligence agencies for evidence relating Trump's surprising claim.
"The President has asked Congress to look into whether or not his campaign was wiretapped by the Obama administration. I will take up that challenge," Graham told CNN. "We sent a letter to the Department of Justice and the FBI asked them for any information that they may have used to obtain a warrant.
"The whole purpose of this," Graham added, "is to find out if a warrant was issued directed at the Trump campaign." Asked whether he would subpoena the information if the agencies do not comply with his request, Graham simply answered "Yes."
And former Director of National Intelligence James Clapper told interviewers that he had no knowledge of wiretaps ordered against Trump or his campaign, adding that he would "certainly hope" he would be aware of any such court orders. For his part, Comey has reportedly asked the Department of Justice to publicly refute Trump's accusations, though no such refutation came about.
Obama is said to be livid at the accusation, and the idea that Trump is questioning the integrity of the Office of the President.