Donald Trump
AFP

The judge overseeing Donald Trump's trial for covering up payments to suppress details of an alleged affair will hear Thursday that the former president has again breached a gag order intended to protect trial participants.

Judge Juan Merchan has already sanctioned the property mogul for defying his order on nine occasions, fining him $9,000 on Tuesday and warning Trump he could face jail for continuing to lash out on social media.

Merchan also instructed Trump to remove seven "offending posts" from his Truth Social account and two from a campaign website. The posts were removed the same day.

He ruled on Tuesday that witness testimony would start later than usual at 1400 GMT to allow the court to hear prosecution claims that Trump has once again breached the gag order.

The gag order imposed on the former president ahead of the trial prohibits him from publicly attacking witnesses, jurors or court staff and their relatives.

On Wednesday, Trump took advantage of a break in the trial to hold a major campaign rally in Wisconsin -- blaming his legal troubles and America's ills on his election rival, President Joe Biden.

"So I got indicted four times, and then I have civil trials -- all coming out of the White House, everything, like a Third World country," he said.

Trump regularly claims that his indictments -- three for alleged cheating in elections and one for hoarding classified documents -- are being orchestrated as part of a political witch hunt, but never offers any evidence.

The real estate tycoon used his rare day on the stump to remind the public of his preferred image as a confident, seasoned campaigner.

His appearance was a cry far from the grim Manhattan courtroom where he is defending against claims he covered up payments to a porn star before the 2016 presidential election.

The court has heard from an eclectic slate of witnesses including a lawyer who claims he helped the porn star at the heart of the case, Stormy Daniels, sell the story of her alleged affair with Trump.

Trump denies the fling.

Prosecutors allege that Trump made the hush money payment to Daniels to silence her about a 2006 tryst at a celebrity golf tournament that could have potentially derailed his 2016 White House bid.

Trump is the first former US president to face criminal charges, and the trial appears to have deeply frustrated the 77-year-old populist.

For two weeks Trump has sat through hours of sometimes technical testimony, visibly irate with no-nonsense Judge Merchan, who has required him to be present.

Before and after each day's proceedings, Trump has assailed journalists outside, venting about his legal problems and myriad other issues.