President Donald Trump blasted the 'bogus' dossier of salacious and unverified information about him in an angry early morning tweet the day after Christmas, calling it a 'tainted' document that the FBI must not use as a basis for investigation.

Trump railed against the dossier as a 'pile of garbage,' bringing up its Democratic funding origins, while going after the FBI for reportedly using the dossier as the foundation for its investigations of Trump campaign officials and associates.

'WOW, @foxandfriends "Dossier is bogus. Clinton Campaign, DNC funded Dossier. FBI CANNOT (after all of this time) VERIFY CLAIMS IN DOSSIER OF RUSSIA/TRUMP COLLUSION. FBI TAINTED,” Trump wrote.

'And they used this Crooked Hillary pile of garbage as the basis for going after the Trump Campaign!'

President Donald Trump went after the salacious and unverified information about him in an angry early morning tweet

Trump fired off the tweet as Republicans in Congress have followed his lead and turned up the heat on top FBI officials over the alleged 'bias' among top agents pursuing the Russia investigation.

Special counsel Robert Mueller has obtained guilty pleas from two Trump associates, including former national security advisor Mike Flynn, for lying to the FBI.

Trump's attack followed a Fox News report that FBI officials had their 'back against the wall' following hours-long testimony by deputy director Andrew McCabe.

The network referenced a Washington Times report.

That report stated that the FBI was declining to repudiate the dossier, which it partially relied on during its investigation of the Trump campaign during the election.

It also stated that the FBI concedes that 'major core charges of election collusion' contained in the original dossier remain unsubstantiated.

Lawmakers have blasted funding sources of the infamous dirty dossier compiled by former British intelligence officer Christopher Steele, and wanted to know if it formed the bases for FISA warrants

Lawmakers want to investigated the infamous dirty dossier, its funding sources, and whether it got used to obtain surveillance warrants. Salacious unproven parts of the dossier have been discredited

The House GOP's probing of the FBI's actions come amid rising Democratic warnings about efforts to tarnish or even push out special counsel Robert Mueller

The Fox anchor relating the report said the FBI was 'admitting they cannot verify the trump dossier.'

The dossier, in additional to containing unverified and salacious information about Donald Trump's alleged conduct in a Moscow hotel room, catalogued various alleged contacts between Trump advisors and the Russians and even alleged pay-offs.

Many of those claims have not yet been substantiated, although Mueller's probe has unearthed multiple contacts between Trump officials and Russians that the officials have now acknowledged took place.

Trump's lawyers continue to predict that Mueller is wrapping up his probe as it relates to anyone in the White House. His lawyers were to have met with Mueller and his team last week.

The dossier was compiled by retired British intelligence officer Christopher Steele. Its murky origins have been revealed to include a Republican donor who hired political intelligence firm Fusion GPS. A Democratic lawyer then provided payments on behalf of the DNC and the Hillary Clinton campaign to continue research on Trump after the primaries.

The information in the dossier, which included allegedly compromising information on Trump, made its way to the FBI, which opened its own investigation of former Trump campaign manager Paul Manafort and other officials.

House Intelligence Chairman Rep. Devin Nunes has taken part in secret meetings with other GOP panel members to attempt to ferret out corruption they believe exists within the FBI and the Justice Department

The dossier got handed over to the FBI during the campaign. During oversight hearings, Republican lawmakers have complained that a tainted document could have been the basis for conducting surveillance on Trump associates.

Special Counsel Robert Mueller's probe has obtained guilty pleas from two Trump associates, including former White House security advisor Mike Flynn.

It has charged former Trump campaign manager Paul Manafort and his one-time deputy, Rick Gates.

The Washington Post reported that House Intelligence chairman Rep. Devin Nunes of California is considering producing a report with other Republicans on alleged 'corruption' at the FBI.

The House GOP's probing of the FBI's actions come amid rising Democratic warnings about efforts to tarnish or even push out Mueller as his investigators make their way through key Trump advisors.

McCabe was interviewed behind closed doors on Tuesday by the House Intelligence Committee, which is conducting one of the main congressional investigations into Russia, the 2016 U.S. election and whether Trump's campaign personnel colluded with the Kremlin.

He also appeared for a closed-door interview on Thursday with the House Judiciary and Oversight Committees after Republicans asked him to discuss the bureau's handling of a probe into Hillary Clinton's use of an illicit private email server when she was secretary of state.

McCabe served as acting director of the FBI after Trump fired former FBI director James Comey in May. In a tweet in July, Trump asked why his Attorney General, Jeff Sessions, did not replace McCabe, who Trump described as Comey's friend.

Trump's tweet came after FBI deputy director Andrew McCabe got grilled in closed-door meetings in Congress

McCabe's wife, Jill, received $700,000 in donations from Virginia Gov. Terry McAuliffe's political action committee and the Virginia Democratic Party for a state Senate race in 2015.

The money was donated before McCabe was promoted to deputy director and assumed a supervisory role in the Clinton email investigation. McAuliffe is a longtime supporter of Clinton and her husband, former President Bill Clinton.

McCabe became acting FBI director last May after Trump fired Comey, who was overseeing the bureau's investigation into Russian election interference. Trump maintains there was no collusion between his campaign and Moscow, and has blasted the investigation as a "witch hunt."

From his South Florida home, where he is spending the holidays, Trump also tweeted that McCabe "is racing the clock to retire with full benefits. 90 days to go?!!!"

The dossier Trump trashed claimed that Russia had gotten compromising information on Donald Trump

McCabe plans to retire in about 90 days, when he becomes fully eligible for pension benefits, The Washington Post reported Saturday. Trump and his Republican allies have made it clear that they want McCabe out of the FBI. But McCabe is a civil service employee who cannot be fired without evidence of wrongdoing.

McCabe was among the candidates Trump interviewed for the FBI director's job after he dismissed Comey. He also has been a focus of Trump's ire for some time.

Trump originally tweeted about McCabe's wife's campaign in July, inaccurately describing the campaign donation as coming from Clinton: "Problem is that the acting head of the FBI & the person in charge of the Hillary investigation, Andrew McCabe, got $700,000 from H for wife!"

In a second tweet that month, the president asked "why didn't A.G. Sessions replace Acting FBI Director Andrew McCabe, a Comey friend who was in charge of Clinton investigation," referring to Attorney General Jeff Sessions.

Republicans charge that an anti-Trump bias exists in the bureau's ranks, citing the campaign donations to McCabe's wife and, more recently, the release of hundreds of text messages between FBI counterintelligence agent Peter Strzok and FBI lawyer Lisa Page.

Strzok and Page used words like "idiot" and "loathsome human" to describe Trump during the campaign.

Strzok was removed the team of special counsel Robert Mueller, who is leading the Russia investigation, over the summer after the text messages surfaced – particularly one that referred to his work as a 'insurance policy' in case Trump won the election.