US Senator Ted Cruz has accused the head of America's broadcast regulator of acting like a mafioso in the suspension of late-night host Jimmy Kimmel - the sharpest attack yet from a conservative Republican on the controversy.

He said Federal Communications Commission (FCC) chairman Brendan Carr's threat to ABC over their comedian's monologue about slain conservative influencer Charlie Kirk was dangerous as hell.

That's right out of Goodfellas, the Texas Republican said, as he affected a mobster's accent.

Other Republicans in Congress have been more muted in their criticism of how the FCC pressed Disney-owned ABC to take action on Kimmel, who was indefinitely suspended on Wednesday.

The row started after Kimmel said in his monologue on Monday that the Maga gang were desperately trying to characterize this kid who murdered Charlie Kirk as anything other than one of them and trying to score political points from it.

He also likened Trump's reaction to the conservative political activist's death to how a four-year-old mourns a goldfish.

Brendan Carr called those comments sick and threatened to take action because the host had appeared to directly mislead the American public.

Conservative critics say Kimmel was pushing a false narrative by suggesting the suspect in the Kirk killing was a Make America Great Again Republican. While the exact motive is still not known, on Sunday - before Kimmel spoke - the Utah governor had said the suspect was indoctrinated by leftist ideology.

On his podcast Verdict with Ted Cruz, the senator emphasized on Friday that he hated what Kimmel said about Kirk, and he is thrilled that he was fired. He also said Carr was a good guy. Cruz warned that if the government gets into the business of banning and regulating what the media says, it could end badly for conservatives.

In the Oval Office, President Donald Trump defended Carr and said I disagree with Ted Cruz, who is ordinarily one of his staunchest allies. Republican Senator Thom Tillis of North Carolina also backed Cruz's criticisms.

The incident raises significant questions about the balance between regulated speech and free expression, suggesting the current political landscape could lead to further confrontations over media integrity.