President Donald Trump's personal attorney, Rudy Giuliani, traded barbs with the Democratic operative and attorney Christopher Hahn during a Fox News interview on Tuesday.

It followed news reports over Giuliani's role in US-Ukrainian affairs amid a whistleblower scandal.

Hahn accused Trump and Giuliani of breaching political norms and said their actions could be grounds for impeachment.

After the two began interrupting each other's rebuttals, a heated Giuliani resorted to an insult: "Shut up, moron. Shut up. Shut up, you don't know what you're talking about."

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President Donald Trump's personal attorney, Rudy Giuliani, traded barbs with the Democratic operative and attorney Christopher Hahn during a Fox News interview on Tuesday that culminated in Giuliani calling Han a "moron" and telling him to "shut up."

The heated exchange followed news reports about the role Giuliani played in US-Ukrainian affairs amid the whistleblower scandal that has engulfed the White House.

Hahn accused Trump and Giuliani of breaching political norms and said their communications with Ukrainian officials regarding a political opponent — former Vice President Joe Biden — could be grounds for impeachment.

Trump earlier acknowledged raising unproven corruption allegations about Biden during a July phone call with Ukrainian President Volodymyr Zelensky.

Trump's acknowledgement has been widely linked to a recently uncovered whistleblower complaint said to allege that the president made a concerning "promise" to a foreign leader. Further attracting scrutiny is that the July call took place soon after the White House withheld millions of dollars in military aid for Ukraine.

Democrats, many of whom have ramped up their calls for impeachment, theorized that Trump was leveraging his political power for Ukraine's help in digging up dirt on the Biden family.

Hahn accused Giuliani of "making things up" in his pursuit of Biden and characterized Giuliani's claims against Biden as "libelous."

"I should sue you for libel," Giuliani said in the exchange.

Read more: 7 Democratic lawmakers who served in the military and intelligence agencies accuse Trump of 'flagrant disregard for the law'

President Donald Trump speaking with members of the media on August 30 at the White House before his departure for Camp David. Getty Images/Alex Wong

After the two began interrupting each other's rebuttals, a heated Giuliani said: "Shut up, moron. Shut up. Shut up, you don't know what you're talking about."

Giuliani described Hahn as a "serial liar" and described being asked by the US State Department "to facilitate a meeting" between Trump and Zelensky.

Giuliani said he met with one of Zelensky's representatives but "never discussed any kind of pressure about a criminal case" or a "quid pro quo."

Giuliani's characterization of his interactions with the State Department contradicts officials who have said he was inserting himself in processes that were only peripherally related to diplomacy — and more relevant to Trump's political opponents.

"Rudy — he did all of this," one official told The Washington Post. "This s---show that we're in — it's him injecting himself into the process."

Giuliani gave himself a positive assessment of his performance in recent days, despite the freewheeling interviews he gave on multiple news networks.

"I sure as heck know how to protect myself and my client," Giuliani said. "It was a perfectly appropriate, Perfectly legitimate, and a completely authorized communication."