President Donald Trump on Saturday acknowledged news reports that his personal attorney Rudy Giuliani may be under investigation by federal investigators, calling the reported probe "shameful."

"So now they are after the legendary 'crime buster' and greatest Mayor in the history of NYC, Rudy Giuliani," Trump wrote in a tweet. "He may seem a little rough around the edges sometimes, but he is also a great guy and wonderful lawyer. Such a one sided Witch Hunt going on in USA. Deep State. Shameful!"

Trump's comments came after news broke Friday in The New York Times that federal prosecutors are investigating Giuliani for potential lobbying law violations as it relates to his work in Ukraine. The Times, citing two anonymous people "familiar with the inquiry," reported the probe focuses on Giuliani's efforts to "undermine" former U.S. ambassador to Ukraine Marie L. Yovanovitch, who testified before three House committees Friday in the impeachment inquiry of Trump.

Trump told Fox News on Saturday that Giuliani is still his attorney, a day after answering that question at the White House by saying he didn't know.

"Yes," Trump told Fox in response to a question about whether Giuliani was still his attorney. "He's a great gentleman he was a great mayor."

The investigation of Giuliani is also, the Times reports, linked to Lev Parnas and Igor Fruman, Ukrainian-born business partners arrested Wednesday in connection with alleged schemes to funnel foreign money to U.S. political campaigns. Parnas and Fruman helped Giuliani meet former Ukrainian prosecutor Yuri Lutsenko as the president's personal lawyer pushed for an investigation into Trump's political rival Joe Biden.

The impeachment inquiry of Trump, which is tied to the president's efforts to get Ukraine to investigate political rivals like Biden, has drawn attention to Giuliani and whether his activities in Ukraine violate a federal law that requires Americans who work on behalf of foreign governments to register with the Justice Department.

Giuliani defended himself against such a crime by claiming to the Times he was working for Trump, not a foreign government.

“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.

Giuliani said Saturday that he has had no contact with federal prosecutors in Manhattan, but he said any such scrutiny was likely politically motivated.

“No, nothing but leaks,” Giuliani said. “It’s a political attack, otherwise why leak it. If it’s an appropriate law enforcement investigation, you try to keep it secret so the subjects aren’t alerted.”

Trump and Giuliani:Donald Trump distances himself from Rudy Giuliani: 'He has been my attorney'

Jon Sale, a former Watergate prosecutor whom Giuliani hired to represent him in the impeachment inquiry, told USA TODAY on Friday that he’s not aware of an investigation into Giuliani. He said Giuliani has not been contacted by investigators in New York.

Representatives for Manhattan U.S. Attorney Geoffrey Berman did not immediately respond to inquiries from USA TODAY. A spokeswoman for the U.S. attorney’s office in the Southern District of New York declined to confirm Friday if Giuliani is under investigation, only saying that the probe into Parnas and Fruman is ongoing.

Giuliani declined to comment on his dealings with Parnas and Fruman, saying they are his clients and much of their communications are bound by attorney-client privilege.

On Friday, Yovanovitch – a career diplomat – spent hours on Capitol Hill giving a deposition for House Democrats' impeachment inquiry.

In her opening remarks, Yovanovitch said she was told by a high-ranking agency official "that the president had lost confidence in me and no longer wished me to serve as his ambassador."

The State Department official "added that there had been a concerted campaign against me, and that the department had been under pressure from the president to remove me since the Summer of 2018," according to her statement. "He also said that I had done nothing wrong and that this was not like other situations where he had recalled ambassadors for cause. I departed Ukraine for good this past May."

Trump indeed pulled Yovanovitch from her Ukraine ambassador post in May.

Giuliani told a Ukrainian journalist that Yovanovitch was "removed ... because she was part of the efforts against the president." Giuliani further targeted Yovanovitch in a packet of "disinformation" that he gave to State Department officials earlier this year. The dossier was full of debunked allegations and political smears targeting the president’s perceived enemies, and it eventually made its way to lawmakers leading the impeachment probe.

After a briefing on the Giuliani dossier by the State Department's chief watchdog, the three chairmen leading the impeachment inquiry said it raised "troubling" new questions about efforts inside and outside the Trump administration to target Yovanovitch and others.

Trump attempted to distance himself from Giuliani on Friday, casting doubts on whether the former New York City mayor was still his lawyer.

Asked whether Giuliani remained his personal attorney, Trump said: “I don’t know.”

“I haven't spoken to Rudy,” Trump told reporters as he was leaving the White House for a political rally in Louisiana. “I spoke to him yesterday, briefly. He's a very good attorney and he has been my attorney, yeah sure.”

Giuliani told USA TODAY shortly afterward that he’s still Trump's lawyer. “He hasn't told me otherwise,” he said.

Contributing: Kristine Phillips, Kevin Johnson, Bart Jansen, Kevin McCoy, Ledyard King, Christal Hayes, John Fritze and Michael Collins