A combative Donald Trump made a rare live appearance on longtime adversary CNN on Wednesday, repeating his false claims about the 2020 election, hurling insults and mocking a former magazine columnist he was found liable of sexually abusing and defaming.

Trump, during a one-hour "town hall" on the cable television network that he regularly denounced as "fake news" while in the White House, took questions on a broad range of subjects including the war in Ukraine, the debt limit, immigration and his multiple legal challenges.

"Most people understand that what happened was a rigged election," Trump said of his 2020 presidential election defeat by Democrat Joe Biden.

If re-elected, he said he would pardon a "large portion" of the hundreds of Trump supporters who have been jailed for their roles in the January 6, 2021 storming of the US Capitol.

"They were there with love in their heart," the 76-year-old Trump said of the rioters who attempted to block the congressional certification of Biden's win.

Trump, the frontrunner for the 2024 Republican presidential nomination, refused to unreservedly commit to accepting the results of the next White House vote when pressed by CNN anchor Kaitlin Collins, the mediator for the event.

"If I think it's an honest election, absolutely I would," Trump said.

The former president also waded into the tense negotiations between the Biden White House and Congress over raising the US debt limit, urging Republican legislators not to do so if Democrats don't agree to spending cuts.

"I say that the Republicans out there congressmen, senators, if they don't give you massive cuts, you're gonna have to do a default," Trump said, before quickly adding that he sees such a scenario as unlikely.

The US government has never intentionally defaulted on its debt, and some economists warn that the effects could be calamitous.

On Ukraine, Trump said Russian leader Vladimir Putin made a "tremendous mistake" by invading but he declined to say who he wanted to win the war or whether he would continue to provide military aid to Ukraine.

"I don't think in terms of winning and losing. I think in terms of getting it settled," he said. "They're dying, Russians and Ukrainians. I want them to stop dying and I'll have that done in 24 hours."

Trump slammed Biden over his handling of immigration saying that Thursday, when a Covid-era policy lapses, will be a "day of infamy" along the US border with Mexico.

"You're going to have millions of people pouring into our country," he said, while suggesting that he would reinstitute a policy of separating families at the border.

"When you have that policy, people don't come," he said. "I know it sounds harsh."

- 'Four more years of that?' -

The CNN event was seen as the first major test of the 2024 campaign for Trump, who has done only a couple of rallies since launching his new White House bid.

Biden, who announced last month that he will seek re-election, responded to Trump's appearance with a fund-raising appeal.

"It's simple, folks," Biden tweeted. "Do you want four more years of that?"

Never Back Down, a political action committee backing Florida Governor Ron DeSantis, a potential rival for the 2024 Republican nomination, called the CNN event "an hour of nonsense that proved Trump is stuck in the past."

The CNN appearance came just one day after Trump was ordered by a New York jury to pay $5 million in damages to E. Jean Carroll, a former columnist for Elle magazine who accused him of raping her in a Manhattan department store changing room in 1996.

Trump vehemently repeated his denials and called Carroll a "wack job."

Trump dismissed other legal challenges he is facing as the work of Democrats out to torpedo his bid to be the Republican standard-bearer in 2024. "They're doing this for election interference," he said.

Trump had a number of testy exchanges with Collins, a former CNN White House correspondent, calling her a "nasty person" at one point, while playing to the friendly Republican crowd, which responded with repeated applause and laughter.

CNN said the audience was made up of New Hampshire Republicans and undeclared voters who plan to vote in the state's 2024 Republican presidential primary, the first in the nation.

CNN has come in for some criticism for giving the twice-impeached Trump a primetime slot but defended the move by saying it plans to provide the same town hall format to other presidential candidates.

Trump sued CNN in October, accusing the network of waging a campaign of "libel and slander" against him and seeking $475 million in punitive damages.