One of Rudy Giuliani's indicted Ukrainian 'fixers' is reportedly prepared to testify before Congress that Rep. Devin Nunes, the Republican ranking member of the House Intelligence Committee and a key ally of President Donald Trump, met with Ukrainian officials to dig up dirt on Joe Biden.

Lev Parnas, who is charged with campaign finance violations, wants to testify that Nunes met last year with the prosecutor who was fired under pressure from Biden when he was vice president, Parnas' lawyer told CNN.

'Mr. Parnas learned from former Ukrainian Prosecutor General Victor Shokin that Nunes had met with Shokin in Vienna last December,' attorney Joseph A. Bondy told the outlet.

'Nunes had told Shokin of the urgent need to launch investigations into Burisma, Joe and Hunter Biden, and any purported Ukrainian interference in the 2016 election,' Bondy said.

Nunes responded by calling the CNN report and a similar one in the Daily Beast 'demonstrably false and scandalous' and vowing to sue both publications.

Rep. Devin Nunes (right) attends the impeachment hearings on Thursday. He reportedly met with a former Ukraine official last year seeking dirt on Joe Biden

Lev Parnas (left) is seen with Rudy Giuliani at Trump International Hotel in DC in September 2018. Parnas is prepared to testify against Nunes

'These demonstrably false and scandalous stories published by the Daily Beast and CNN are the perfect example of defamation and reckless disregard for the truth,' Nunes told Breitbart News late Friday night.

'Some political operative offered these fake stories to at least five different media outlets before finding someone irresponsible enough to publish them. I look forward to prosecuting these cases, including the media outlets, as well as the sources of their fake stories, to the fullest extent of the law,' he continued.

'I intend to hold the Daily Beast and CNN accountable for their actions. They will find themselves in court soon after Thanksgiving.'

Bondy has repeated the Parnas' allegations to other news outlets, including NBC News.

A spokesman for Nunes did not immediately respond to a request for comment from DailyMail.com on Friday night.

Biden has bragged openly of how he threatened to withhold loan guarantees to ensure Shokin was removed from office in early 2016.

Giuliani, Trump's personal attorney, has pursued the theory that Shokin was removed to end investigations into Burisma, the gas company where Biden's son Hunter sat on the board.

Biden supporters dismiss that claim as a conspiracy theory, saying that Biden put pressure on Ukraine to oust Shokin was because the prosecutor failed to tackle corruption.

Nunes has been a key Trump defender during the impeachment hearings, which center on Trump's push to have the Ukraine investigate whether Biden acted corruptly in Shokin's firing.

Biden (left) has bragged openly of how he withheld loan guarantees to ensure Shokin (right) was removed from office in early 2016, but insists his motive was legitimate

Parnas (center) and Giuliani (right) meet with the chief rabbi of Ukraine Moshe Azman in 2018

The latest allegation that Nunes met with Shokin in similar efforts to dig dirt on Biden threatens to put the California Republican in a politically precarious position on the Intelligence Committee.

Bondy has already called for Nunes to recuse himself from the impeachment probe, in a tweet on Friday.

The lawyer also tweeted an appeal to Intelligence Committee Chairman Adam Schiff, who is leading the impeachment inquiry, asking him to call Parnas to testify.

'His information completes the narrative—it’s non-hearsay, not part of the GOP “rope-a-dope,” and in the greatest of our national interests,' Bondy wrote.

According to Bondy, Nunes met with Shokin in Vienna in December 2018.

Congressional travel records show that Nunes and three aides traveled to Europe from November 30 to December 3, 2018.

The records do not show what countries Nunes visited, a detail that the Congressman is not required to disclose. The trip cost taxpayers about $63,000.

At the time of the trip, Nunes was chairman of the Intelligence Committee. In January, Schiff took over as chairman of the powerful committee.

Nunes allegedly made his own investigation into Joe Biden and his son Hunter (above)

According to Bondy, Parnas spoke with Nunes, who said he was conducting his own investigation into the Bidens.

Parnas said that Nunes was basing his investigation partly off of information from John Solomon, who has written extensively about alleged Biden corruption in columns for The Hill.

Giuliani has said that he opened his freelance probe in Ukraine to produce evidence to defend Trump against the investigation of special counsel Robert Mueller.

Guiliani's Ukraine efforts sprawled into inquires into Biden and involved him with various factions in the country.

To help negotiate local politics, Giuliani enlisted Parnas and Igor Fruman, two naturalized American citizens born in the former Soviet Union.

In October, Parnas and Fruman were arrested on multiple campaign finance charges, many of which apparently stemmed from their efforts to curry favor for a legal marijuana venture in Nevada.

Parnas and Fruman are currently under house arrest, and have pleaded not guilty.