Giuliani under investigation for alleged campaign finance, lobbying breaches: report

President TrumpDonald John TrumpLawmakers prep ahead of impeachment hearing Democrats gear up for high-stakes Judiciary hearing Warren says she made almost M from legal work over past three decades MORE’s personal attorney Rudy GiulianiRudy GiulianiNunes: 'Sickening' that Schiff obtained his phone records Meadows: 'I don't see a single Republican defecting on impeachment' Inventing the 'Deep State' and draining the real one MORE is under investigation by federal prosecutors over possible campaign finance violations and accusations he failed to register as a foreign agent, Bloomberg reports.

Multiple U.S. officials told the outlet that the probe into Giuliani’s financial dealings could also lead to charges of violating bribery or conspiracy laws, with one adding that his work alongside the president has raised counterintelligence concerns.

The former New York City mayor is at the heart of House Democrats’ impeachment inquiry into Trump, as investigators look into Giuliani's role in efforts to pressure Ukrainian President Volodymyr Zelensky to investigate one of the president's chief political rivals, former Vice President Joe BidenJoe BidenBiden: Buttigieg 'doesn't have significant black support even in his own city' Biden: 'I'd add' Warren to my list of potential VP picks How can top Democrats run the economy with no business skill? MORE

Giuliani, if indicted, would likely affect Trump's defense strategy amid the ongoing probe.

“I would not be surprised if he gets indicted,” Mimi Rocah, a former federal prosecutor with the U.S. Attorney’s Office for the Southern District of New York, told Bloomberg. “It’s clear Giuliani is up to his ears in shady stuff and there’s tons of smoke.”

Federal prosecutors in Manhattan are also investigating whether Giuliani broke lobbying laws in dealing with Ukraine, as well as his efforts to undercut Marie Yovanovitch, the U.S. ambassador to Ukraine who was ultimately recalled in the spring as Trump sought to pressure the country to probe Biden.

Two of Giuliani’s associates, Lev Parnas and Igor Fruman, have been charged with campaign finance violations in funneling hundreds of thousands of dollars into a pro-Trump political action committee.

Parnas’s attorney has said his client warned Ukrainian officials that the Trump administration would freeze military aid to Ukraine unless Kyiv announced an investigation into Biden.

In an op-ed published Tuesday, one day before the House held its first public hearings in the impeachment inquiry, Giuliani slammed the “unprecedented, constitutionally questionable” probe. He has maintained the July 25 call between Trump and Ukraine that lies at the heart of the inquiry was “innocent.”

Updated at 8:25 p.m.