WASHINGTON – The lawyer for an indicted business associate of Rudy Giuliani said his client is prepared to testify under oath that aides to Rep. Devin Nunes, the top Republican on the House Intelligence Committee, scrapped a trip to Ukraine this year when they realized it would mean notifying Democratic Chairman Rep. Adam Schiff.

Lev Parnas would tell Congress that the purpose of the planned trip was to interview two Ukrainian prosecutors who claim to have evidence that could help President Donald Trump's reelection campaign, Parnas' attorney, Joseph Bondy, told CNBC. Nunes is one of Trump's most outspoken defenders in Congress. Giuliani is one of the president's personal lawyers.

But when Nunes' staff realized that going to Ukraine themselves would mean alerting Schiff to their plans, they instead asked Parnas to set up the meetings for them over phone and Skype, which he did, according to Bondy.

The Intelligence Committee is leading the House's impeachment inquiry into Trump. It wrapped up two weeks of public hearings Thursday during which several Trump administration officials described a pressure campaign to influence Ukraine into saying it would investigate former Vice President Joe Biden, the frontrunner for the 2020 Democratic presidential nomination, and a discredited conspiracy theory regarding the 2016 election.

Bondy is representing Parnas against federal campaign finance charges in New York. Parnas has pleaded not guilty to charges of illegally funneling money from a Ukrainian government official to Republican candidates in the U.S., including Trump.

For more than a year, Parnas has also worked closely with Giuliani to dig up dirt on Biden and his son Hunter in Ukraine in advance of the 2020 presidential election, according to Bondy. During that time, Trump and his allies in Congress have pushed unfounded claims that Biden intervened in a Ukrainian criminal investigation, and that Ukraine meddled in the 2016 U.S. presidential election.

The Nunes team's scrapped trip to Ukraine has not been previously reported, nor have the meetings that Bondy said his client arranged in place of the overseas trip. The meetings took place in late March, and Derek Harvey, a senior investigator for Nunes, represented the congressman, according to Bondy. One of the meetings was with Ukraine's chief anti-corruption prosecutor, Nazar Kholodnytsky, and it was held over Skype, Parnas would tell Congress. The second, Bondy said, was a phone call Parnas arranged for Harvey with a deputy in Ukraine's Prosecutor General's office, Konstantin Kulik.

Both Kulik and Kholodnytsky have repeatedly claimed they witnessed corruption by Democratic operatives in Ukraine during the 2016 election. Neither official has produced evidence to support his account. A Nunes spokesman did not respond to several requests for comment about what Parnas would reveal to Congress.

According to Bondy, Parnas says he began working with Harvey after Nunes, of California, and his staff traveled to Vienna in late November to meet with another potential source of political dirt on Democrats: former Ukrainian prosecutor Viktor Shokin, who claims that Biden demanded his firing because Shokin was secretly investigating a company, Burisma, that employed Biden's son Hunter.

CNN first reported Friday that Parnas wanted to testify before the House Intelligence Committee about the Vienna trip. Since then, Nunes has threatened to sue both CNN and The Daily Beast, which also reported on Parnas' allegations.

Asked point blank during an interview Sunday whether he met with Shokin in Vienna, Nunes refused to answer, telling Fox News that Parnas was "a criminal," and that he would not "debate this out with the public media when 90% of the media are totally corrupt."

The latest allegations about the planned trip to Ukraine this spring, however, suggest that Nunes' purported efforts to dig up dirt on Biden and Democrats did not end with the Vienna trip.

They also potentially implicate Nunes and his committee staff in the same events the committee is currently investigating. Specifically, the monthslong effort by Trump, Giuliani and others to get Ukrainian officials to help them dig up dirt on Biden, and to validate far-right conspiracies about Ukraine and the 2016 election.

Trump raised both of these issues on a phone call July 25 with Ukraine's president, Volodymyr Zelenskiy, prompting a whistleblower complaint that sparked the current impeachment investigation into the president.

During the past two weeks, nearly a dozen current and former officials in the Trump administration testified before Nunes and the rest of the Intelligence Committee about what they say was a far-reaching effort to exert pressure on Ukraine to announce the investigations Trump wanted, up to and including withholding congressionally appropriated foreign aid to the war-torn country.

Over the course of three days of public hearings last week, Nunes used the bulk of his allotted time to attack Democrats and the media, and to repeat the same unfounded claims about Democrats and Biden. At no point did Nunes ever mention that he or his staffers met with the three Ukrainian officials, some of whom were mentioned by name during testimony.

Speaking to CNBC, Bondy said Parnas merely wants an opportunity to testify under oath before the Intelligence Committee about his and Giuliani's activities in Ukraine. But so far, it's not clear whether Schiff will call him in. Bondy said Parnas has responded to a subpoena he received this fall from the committee by turning over thousands of pages of records to back up his account of events.

Asked whether he planned to ask Parnas in to testify, Schiff, of California, said Sunday that the committee wants to review the documents he produces first, before deciding whether to proceed with an interview. Schiff appeared on NBC's "Meet the Press" on Sunday.

Meamwhile, Rep. Adam Smith, D-Wash., the chairman of the House Armed Services Committee, said Sunday that Nunes would "likely" face a House ethics probe over allegations he sought to dig up dirt on Biden.

Reached for comment about Parnas' latest allegations, a spokesman for the Intelligence Committee referred CNBC to Schiff's earlier remarks.

Parnas wants to provide the committee with "truthful and important information that is in furtherance of justice," Bondy told CNBC.

"We have great faith that, in the end, the proper choice will be made as to when and whether to hear Mr. Parnas," he said.