Former US president Donald Trump has marked the third anniversary of the assault on the US Capitol on January 6 2021 by casting the migrant surge on the southern border as the “real” insurrection.

Just over a week before the Republican nomination process begins with Iowa’s caucuses, Mr Trump continued to claim that countries have been emptying jails and mental institutions to fuel a record number of migrant crossings.

There is no evidence that this is the case.

Mr Trump said in Iowa: “When you talk about insurrection, what they’re doing, that’s the real deal. That’s the real deal. Not patriotically and peacefully — peacefully and patriotically.”

Donald Trump
Mr Trump is seen as the frontrunner for the Republican nomination (AP)

He was quoting from his speech on January 6, before a violent mob of his supporters stormed the Capitol as part of a desperate bid to keep him in power after his 2020 election loss to Joe Biden.

Mr Trump’s remarks came a day after Mr Biden delivered a speech near Valley Forge, Pennsylvania, where he cast Mr Trump as a grave threat to democracy and called January 6 a day when “we nearly lost America – lost it all”.

With a likely rematch of the 2020 election looming, both Mr Biden and Mr Trump have frequently invoked January 6 on the campaign trail.

Mr Trump, who is under US federal indictment for his efforts to overturn his 2020 loss to Mr Biden, has consistently downplayed or spread conspiracy theories about a riot in which his supporters – spurred by his lies about election fraud – tried to disrupt the certification of Mr Biden’s victory.

The former leader also continued to bemoan the treatment of those who have been jailed for participating in the riot, again labelling them as “hostages”.

Mr Trump speaks
Mr Trump spoke at a rally at Des Moines Area Community College in Newton, Iowa (AP)

More than 1,230 people have been charged with federal crimes connected to the violence, including assaulting police officers and seditious conspiracy.

Mr Trump was holding a pair of commit-to-caucus events in Newton in central Iowa and Clinton in the state’s far east just over a week before voting begins on January 15.

Earlier on Saturday, he courted young conservative activists in Des Moines, speaking to members of Run GenZ, an organisation that encourages young conservatives to run for office. Many in the audience at the Embassy Suites hotel in Des Moines seemed surprised to see Mr Trump, whose visit had not been previously announced.

Mr Trump’s campaign is hoping to turn out thousands of supporters who have never caucused before as part of a show of force aimed at denying his rivals momentum and demonstrating his organising prowess heading into the general election.

His chief rivals, former United Nations Ambassador Nikki Haley and Florida governor Ron DeSantis, were also campaigning in the state as they battle for second place in hopes of emerging as the most viable alternative to Mr Trump, who is leading by wide margins in early state and national polls.

Mr Trump has used the trip to step up his attacks against Ms Haley, who has been gaining ground.

Ron DeSantis and Nikki Haley
Ron DeSantis and Nikki Haley are Mr Trump’s main rivals for the Republican nomination (AP)

He again cast her as insufficiently conservative and a “globalist” beholden to Wall Street donors, and accused her of being disloyal for running against him.

“Nikki will sell you out just like she sold me out,” he charged.

On Friday night, Mr Trump highlighted several recent Haley statements that drew criticism, including her comment that voters in New Hampshire correct Iowa’s mistakes (“You don’t have to be corrected,” he said) and her failure to mention slavery when asked what had caused the Civil War.

“I don’t know if it’s going to have an impact, but you know like … slavery’s sort of the obvious answer, as opposed to her three paragraphs of bullshit,” he told a crowd Friday.

In Newton, he said that he was fascinated by the “horrible” Civil War, which he suggested he could have prevented.

“It’s so fascinating,” he said. “It’s just different. I just find it… I’m so attracted to seeing it… So many mistakes were made. See, that was something I think could have been negotiated, to be honest with you.”

Ms Haley’s campaign has pointed to his escalating attention, including a new attack ad, as evidence Mr Trump is worried about her momentum.

“God bless President Trump, he’s been on a temper tantrum every day about me … and everything he’s saying is not true,” Ms Haley told a crowd Saturday in North Liberty, Iowa.