A high-ranking House Democrat said Saturday it’s “quite likely” Rep. Devin Nunes (R-Calif.) will face an ethics investigation over allegations that he met with an ex-Ukrainian official to obtain information about former vice president Joe Biden and his son.

Rep. Adam Smith (Wash.), the chairman of the House Armed Services Committee, appeared on MSNBC where he was asked whether Nunes could face a House inquiry. “Quite likely, without question,” Smith said.

The allegation that Nunes, the top Republican on the House Intelligence Committee, met with a former Ukrainian prosecutor last year to discuss the Bidens came from the attorney for Lev Parnas, one of two Soviet-born associates of Rudolph W. Giuliani who were indicted on charges they broke campaign finance law.

Parnas’s attorney, Joseph Bondy, told The Washington Post that Ukraine’s former top prosecutor, Viktor Shokin, informed Parnas that he had met with Nunes in Vienna in December 2018.

Bondy also said that a top aide to Nunes, Derek Harvey, sometimes joined a group that met frequently in spring 2019 at the Trump International Hotel in Washington, D.C., to discuss the Biden matter, among other topics. The group, according to Bondy, was convened by Giuliani, Trump’s personal attorney, and included Parnas, his business associate Igor Fruman, as well as journalist John Solomon and the husband-and-wife legal team of Joe diGenova and Victoria Toensing.

The information about Nunes’s meeting with Shokin and Harvey’s meetings with Giuliani were first reported by CNN on Friday.

Nunes declined to comment. He did, however, strongly push back on the story to the conservative outlet Breitbart News and threatened to sue CNN for reporting it. He also threatened to sue the Daily Beast for a story linking him and Parnas.

“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 said, according to Breitbart. “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.”

An individual close to Shokin also denied the story.

“This meeting never took place. Viktor Shokin doesn’t know and hasn’t even heard of this person,” said the individual, who spoke on the condition of anonymity to speak freely, referring to Nunes.

Giuliani, appearing on Fox News on Saturday, also said he didn’t believe that Nunes met with Shokin.

“Devin Nunes says he didn’t meet with Shokin. I have no reason to believe that he did,” Giuliani said, adding, “If he did, there would’ve been nothing wrong with it.”

The allegation about Nunes comes as the House moves swiftly in its impeachment investigation of President Trump. The inquiry, triggered by a whistleblower’s complaint, focuses on Trump’s pressure campaign to get Ukrainian President Volodymyr Zelensky to publicly announce investigations into 2020 presidential rival Joe Biden and his son Hunter, and the debunked conspiracy theory that Ukraine interfered in the 2016 election.

At stake at the time of Trump’s July 25 call with Zelensky was nearly $400 million in congressionally appropriated military aid and a long-sought invitation for a face-to-face meeting of the two leaders in Washington.

“I understand a lot of this is about Joe Biden but the bigger thing is about what President Trump and the Russians and all these people have been doing … is a systematic problem that is a threat to the country because of what Russia is doing to democracy,” Smith said in the MSNBC interview.

Rep. Jackie Speier (D-Calif.), a member of the House Intelligence Committee, tweeted, “If Devin Nunes was using taxpayer money to do ‘political errands’ in Vienna for his puppeteer, Donald Trump, an ethics investigation should be initiated and he should be required to reimburse the taxpayers.”

And in an interview with National Public Radio on Saturday, Rep. Joaquin Castro (D-Tex.), another member of the committee, said the panel should hear from Parnas.

“I think it would be valuable to hear from him because we want to know just how far this work extended, how many people were doing the president’s dirty work here,” Castro said.

Shokin is a key figure in Giuliani’s effort to press the Ukrainians to open an investigation into Biden.

He was fired as Ukraine’s Prosecutor General in March 2016, after a pressure campaign from Ukraine’s western allies, led by Biden. Shokin has publicly accused Biden of engineering that effort to protect his son Hunter, who was serving on the board of the Ukrainian energy company Burisma.

Bondy’s allegation about Nunes and Shokin appears to be part of an aggressive campaign he has mounted in recent days to persuade Democrats in Congress to call Parnas to testify. He has been tweeting directly at members of Congress, using the hashtag #LetLevSpeak. He has said Parnas would be willing to testify, provided he was given an accommodation to allow him to avoid self-incrimination. That would likely require Congress giving him immunity for his testimony.

A spokesman for Intelligence Committee Chairman Adam B. Schiff (D-Calif.) declined to comment on whether Parnas would be asked to testify or on the Nunes allegation. House Speaker Nancy Pelosi (D-Calif.) and Minority Leader Kevin McCarthy (R-Calif.) did not respond to requests for comment.

If the House launched an ethics investigation into Nunes it would be the second time his ethics were questioned during the Trump era. In 2017, Nunes was accused of giving classified information to the White House about the Intelligence Committee’s work on Russian interference in the 2016 election.

The House Ethics Committee cleared Nunes of wrongdoing in December 2017, saying he had not disclosed classified information or violated House rules when he publicly discussed foreign surveillance reports.

The new information about Nunes, if true, would suggest that by the time Giuliani spoke to Shokin in January 2019, the former prosecutor had already had a conversation with a key congressional ally of Trump.

Giuliani has cited Shokin’s unproven allegations against Biden as the central exhibit of his argument that Biden acted inappropriately in Ukraine. Giuliani first debriefed Shokin on those allegations in a Skype phone call that January that Parnas has said he helped arrange. The interview had to be conducted remotely after Shokin was denied a visa to travel to the United States because of corruption allegations.

U.S. and Ukrainian officials have said the investigation into Burisma and its CEO was actually dormant at the time of Shokin’s removal. George Kent, a top State Department official, testified to Congress that it was believed at the time that Ukrainian prosecutors in Shokin’s office had accepted bribes in exchange for halting an effort to recover assets from the company’s CEO and went unpunished — a development that helped shape the international consensus that Shokin tolerated corruption and should be removed.

Former ambassador Marie Yovanovitch testified that the Shokin visa decision was a routine one made by consular officials but that Giuliani attempted to appeal it unsuccessfully to both Secretary of State Mike Pompeo and the White House. Parnas has said Giuliani’s anger over the Shokin visa helped fuel his desire to see Yovanovitch removed. She was abruptly pulled from her post earlier this year.

After the intelligence agency whistleblower’s complaint over Trump’s Ukraine pressure campaign emerged publicly, Parnas and Giuliani seemed to continue to believe that Shokin’s account could help sway Americans to support Trump’s effort to get an investigation into the Bidens.

According to people familiar with the matter, Parnas and Fruman planned to travel to Vienna on Oct. 9 and meet with Giuliani so they could organize an interview for Shokin with Fox News’ Sean Hannity. Instead, Parnas and Fruman were arrested at Dulles International Airport, as they prepared to board their flight to Europe.

David Stern and Robert Costa contributed to this report.