Donald Trump may have skipped the debate with his fellow Republican election hopefuls, but the former president had plenty to say in a separate interview on Thursday (AEDT).

Mr Trump appeared in an online interview peppered with his election lies, attacks on his rivals and lavish praise for the crowd of supporters he spoke to before they stormed the US Capitol.

In a pre-recorded conversation with former Fox News host Tucker Carlson, Mr Trump said he was sitting out the first Republican presidential debate in Milwaukee because his poll numbers showed him far ahead of his rivals.

The interview had about 74 million views during its 46 minutes.

Meanwhile, his fellow potential candidates exchanged sharp attacks as they jockey for position for the party’s 2024 nomination.

In his interview, which was aired on the former Twitter platform now called X, Mr Trump seemed to indulge a suggestion from Carlson that his political opponents might try to end his life.

“They’re savage animals. They are people that are sick. Really sick. You have great people in the Democrat Party, you have great people that are Democrats,” he said.

“But I’ve seen what they do, I’ve seen the lengths that they go to.”

Mr Trump also used the interview to venerate his supporters charged with crimes related to the deadly riot at the US Capitol on January 6, 2021 and downplayed the violence that day.

“People in that crowd said it was the most beautiful day they’ve ever experienced. There was love in that crowd. There was love and unity,” he said of the supporters he addressed on the morning before they marched to the Capitol.

“I have never seen such spirit and such passion and such love. And I’ve also never seen, simultaneously, and from the same people, such hatred of what they’ve done to our country.”

Mr Trump attacked some of his rivals, calling former Arkansas Governor Asa Hutchinson “nasty,” and cited him as an example of someone who shouldn’t be on the debate stage, along with former New Jersey Governor Chris Christie.

Both Mr Christie and Mr Hutchinson have been critical of Mr Trump and said he shouldn’t be running for president.

At the actual debate, meanwhile, Vivek Ramaswamy, the 38-year-old tech entrepreneur and political neophyte who has shown surprising strength in recent polls, faced a series of insults from some of his more experienced rivals.

“We don’t need to bring in a rookie,” former vice president Mike Pence said, while Mr Chris Christie accused Mr Ramaswamy of sounding “like ChatGPT,” a reference to artificial intelligence.

For his part, Mr Ramaswamy fired back by emphasising his status as an outsider, calling everyone else on stage “bought and paid for” and accusing Florida Governor Ron DeSantis – who stands in a distant second place behind Trump – of being a “super PAC puppet,” a reference to independent political action committees that typically raise unlimited sums of money from corporations and individuals.

The barbs underscored the opportunity that each candidate had to make a national impression, with Mr Trump choosing to skip the debate at Fiserv Forum in Milwaukee, home to next year’s Republican National Convention. But they also risked further cementing Trump’s sizeable lead in opinion polls by tearing one another down rather than the former president.

With the election more than 14 months away, Mr Trump remains the clear-cut leader among Republican voters despite his four criminal indictments.

The candidates also went after Democratic President Joe Biden from the outset. Moderators Martha MacCallum and Bret Baier, both Fox News hosts, started the debate by asking about the US economy.

“We must reverse Bidenomics so that middle-class families have a chance to succeed again,” Mr DeSantis said. 

With Mr Trump absent, Republican candidates including former South Carolina Governor Nikki Haley and US Senator Tim Scott of South Carolina were seeking to displace Mr DeSantis as the most plausible Trump alternative.

The debate, four months before the first Republican presidential nominating contest in Iowa, took place a day before Mr Trump plans to surrender in Atlanta to face charges he sought to overturn his 2020 election loss in the state. That timing will put him back in the spotlight just as his rivals are hoping to raise their profiles.

In the most recent Reuters/Ipsos poll released this month, Mr Trump held 47 per cent of the Republican vote nationally, with Mr DeSantis dropping six percentage points from July to 13 per cent. None of the other candidates has broken out of single digits.

-with AAP