Federal prosecutors from the Southern District of New York are investigating whether Rudy Giuliani, President Donald Trump's personal lawyer and the former mayor of New York, broke laws governing foreign lobbying related to his work in Ukraine, The New York Times reported Friday night.

Two sources familiar with the investigation told The Times that investigators are looking into his role in the recall of former US ambassador to Ukraine Marie L. Yovanovitch, who was removed this spring before her post was up.

Giuliani has admitted that he sought dirt on political adversaries including former Vice President Joe Biden and his son Hunter, along with Yovannovitch — and he had contact with former Ukrainian prosecutor Yuriy Lutsenko.

"Look, you can try to contort anything into anything, but if they have any degree of objectivity or fairness, it would be kind of ridiculous to say I was doing it on Lutsenko's behalf when I was representing the president of the United States," Giuliani told The Times.

Visit Business Insider's homepage for more stories.

Federal prosecutors from the Southern District of New York are investigating whether Rudy Giuliani, President Donald Trump's personal lawyer and the former mayor of New York, broke laws governing foreign lobbying, The New York Times reported Friday night.

The investigation is related to his work with Ukraine; two sources familiar with the investigation told The Times that investigators are looking into his role in the recall of former US ambassador to Ukraine Marie L. Yovanovitch, who has been a foreign service officer for 33 years and was removed this spring before her post was up.

Yovannovitch appeared for a nine-hour, closed-door deposition on Capitol Hill related to an impeachment inquiry into President Trump. In her opening statement, which was released by Politico, she said that Deputy Secretary of State John Sullivan told her she "had done nothing wrong" and said there was a "concerted campaign' to remove her, and that the department had been "under pressure from the President to remove [her] since Summer of 2018."

Read more: Trump says he doesn't know if Rudy Giuliani is still his lawyer amid reports that Giuliani is under federal investigation

Earlier this week, two of Giuliani's associates Lev Parnas and Igor Fruman were arrested on suspicion of trying to funnel foreign money into a pro-Trump super PAC and other entities to gain leverage in US political circles. Prosecutors also allege Parnas and Fruman tried to influence US-Ukraine relations. It was previously reported that prosecutors are examining Giuliani's relationship with the men.

Giuliani has admitted that he sought dirt on political adversaries including former Vice President Joe Biden and his son, Hunter, along with Yovanovitch — and he had contact with former Ukrainian prosecutor Yuriy Lutsenko. This information was allegedly shared with a columnist and government officials.

"Federal law requires American citizens to disclose to the Justice Department any contacts with the government or media in the United States at the direction or request of foreign politicians or government officials, regardless of whether they pay for the representation," The New York Times reported.

However, Giuliani denies any wrongdoing. "Look, you can try to contort anything into anything, but if they have any degree of objectivity or fairness, it would be kind of ridiculous to say I was doing it on Lutsenko's behalf when I was representing the president of the United States," he told The Times.

Giuliani's dealings with Ukraine are already under scrutiny.

Trump and Giuliani's efforts to pressure Ukraine to investigate the Bidens are at the center of an explosive whistleblower complaint that a US intelligence official filed against Trump in August.

Among other things, the complaint alleged that the president abused his power to "solicit interference from a foreign country in the 2020 US election" during a July 25 phone call with Ukrainian President Volodymyr Zelensky.

Read more: 2 of Rudy Giuliani's associates who prosecutors say helped him dig up dirt on Joe Biden have been charged with campaign finance violations

Giuliani was mentioned 31 times in the complaint and is described as a "central figure" in Trump's effort. The complaint said Attorney General William Barr "appears to be involved as well."

Giuliani has said that he got involved in Trump's efforts only after State Department officials asked him to do so. Text messages between several top US diplomats and Giuliani that were released last week confirmed Giuliani's claim.

The whistleblower's complaint is at the heart of a brewing congressional impeachment inquiry looking at whether Trump used his public office for private gain. House Democrats sent out a flurry of subpoenas and document requests, but the White House said earlier this week that it would not cooperate with what it views as a "partisan and unconstitutional" process.