US President Donald Trump has accused top officials of politicising FBI and justice department investigations to damage his Republican party.
“The top Leadership and Investigators of the FBI and the Justice Department have politicized the sacred investigative process,” he tweeted.
He is expected to approve releasing a memo that suggests the FBI abused its powers to spy on one of his aides.
Democrats say the document is aimed at derailing investigations into Mr Trump.
They portray the memo, commissioned by the Republican head of the House Intelligence Committee, Devin Nunes, as an attempt to undermine a federal inquiry into allegations that the Trump campaign colluded with Russia during the 2016 election campaign.
However, another top Republican, House Speaker Paul Ryan, played down the potential impact of the memo’s publication on the inquiry led by Special Counsel Robert Mueller.
He said Congress had a duty to see surveillance powers were used correctly.
Approved by the House Intelligence Committee on Monday, the document reportedly accuses the FBI (Federal Bureau of Investigation) and justice department of misleading a judge in March of last year while seeking to extend a surveillance warrant against Carter Page.
The memo is said to argue the FBI and justice department did not tell the judge that some of their justification for the warrant relied on a much-disputed Trump dossier.
Compiled by a former British intelligence agent, Christopher Steele, that dossier was financed in part through the campaign of Democratic presidential candidate Hillary Clinton to dig up dirt on Mr Trump.
Unnamed sources told Reuters news agency the Republican memo was misleading because all the dossier excerpts used in the FBI warrant application were independently confirmed by US intelligence.