A Fox News panel devolved into a shouting match when President Trump’s personal attorney Rudy Giuliani engaged with contributor Chris Hahn in a tense argument over the former New York City mayor’s communications with Ukrainian officials.

“I’d like to say to you, Mr. Hahn, I should sue you for libel,” Giuliani said, with Hahn sarcastically responding, “Oh, please.”

“You usually say incredibly stupid things,” Giuliani continued.

“You’re a public figure, so then you know the libel law,” Hahn said, to which Giuliani responded, “Shut up, shut up, you don’t know what you’re talking about, idiot!"

Earlier in the show, Fox News host Laura Ingraham had Giuliani on by himself to discuss the Ukraine controversy that has led to an impeachment inquiry against the president. "I never talked to a Ukrainian official until the State Department called me and asked me to do it," he said.

When Hahn, a former aide to Senate Minority Leader Chuck Schumer, came on the show along with former top federal prosecutor Andrew McCarthy, he claimed Giuliani said he was directed by the State Department to get evidence on Trump's political opponent and that Giuliani was "making things up."

Soon after Giuliani was brought onto the panel he said Hahn’s contention that he was sent to dig up “political dirt” on former Vice President Joe Biden was false.

“Here’s why I was asked by the State Department — it’s all documented — they called me to facilitate a meeting between the president and Mr. Zelensky to help do that,” Giuliani said. “I met with the representative of Mr. Zelensky. We never discussed any kind of pressure about a criminal case, we never discussed any kind of quid pro quo or pressure.”

“You don’t know what you are talking about,” Giuliani directed to Hahn, before the two began yelling over each other.

“OK, guys, you’ve got to stop,” Ingraham broke in.

At one point, Hahn tells Giuliani, “You’re ruining your reputation, Mr. Mayor! And it is time for you to take a step back and please stop going on like this.”

“You may have had respect for me, but I don’t have any respect for you,” Giuliani said to Hahn. “Now the simple fact is the fact is that Joe Biden committed enormously serious crimes.”

Over the past few months, Giuliani has met with Ukrainian officials, encouraging them to investigate whether there was any impropriety when Biden threatened to withhold $1 billion in U.S. loan guarantees if Ukraine did not fire its top prosecutor Viktor Shokin, who had undertaken an anti-corruption investigation into the owner of Burisma Holdings, which had employed Biden's son, Hunter, as a board member in 2014.

Giuliani, who also says there may have been collusion between Ukrainian officials and the Hillary Clinton campaign to release damaging information about former Trump campaign manager, Paul Manafort, who is in prison for illegal lobbying and financial crimes, says he has evidence to support his inquiries.

Giuliani is at the center of a controversy stemming from a July call Trump had with Ukraine's president in which he reportedly pressed for an investigation into the Bidens.

Democrats are concerned that Trump leveraged millions of dollars in military aid to pressure Ukraine to look into a political rival who seeks to challenge him in the 2020 presidential election. Ukraine's foreign minister has said there was no pressure by Trump during the call, but Democrats want to see the transcript as well as a whistleblower complaint that reportedly relates to his communications with Ukraine. They are led by House Speaker Nancy Pelosi, who on Tuesday said she supports an impeachment inquiry.

So far, the Trump administration has refused to give Congress the whistleblower complaint, citing jurisdictional issues, but Trump says he will release the transcript of his call with Ukrainian President Volodymyr Zelensky to show he did nothing wrong, and a Politico report out late Tuesday said the White House is preparing to release the complaint. The White House is also expected to release a document to show the whistleblower had "political bias," according to Fox News.