Donald Trump has declared himself a “political prisoner” and issued a rallying call for “10 million true MAGA patriots” to chip into his fundraising after Thursday’s history jury verdict.

“I’M A POLITICAL PRISONER! I was just convicted in a RIGGED political Witch Hunt trial: I DID NOTHING WRONG!” the former US president wrote in a a message released by the Trump National Committee Joint Fundraising Committee on Thursday (US time) in the hours after the verdict.

It went on, in all capitals:

“YOUR SUPPORT IS THE ONLY THING STANDING BETWEEN US AND TOTAL TYRANNY! … So I need 10 MILLION TRUE MAGA PATRIOTS to chip in and proudly shout: I STAND WITH TRUMP!”

The appeal apparently worked, as WinRed, the official Republican Party donation platform, was crashed just minutes after Trump’s appeal dropped.

“The American people see through Crooked Joe Biden’s rigged show trial,” Trump’s campaign posted on the social platform X.

“So many Americans were moved to donate to President Trump’s campaign that the WinRed pages went down. We are working on getting the website back online as quickly as possible.”

Trump campaign co-manager Chris LaCivita urged supporters to “log back on and try again” if they got error messages.

A post from Trump’s Truth Social platform after the verdict.

It is far from unusual for Trump to try to turn his myriad legal problems into campaign fundraising pitches. He used his mug shot after his Georgia indictment last year to bring in millions of dollars in campaign cash, and his campaign had been widely expected to try to capitalise on outrage at Thursday’s verdict.

Earlier, Trump became the first US president to be convicted of a crime after a New York jury unanimously found him guilty of falsifying documents to cover up a payment to silence a porn star ahead of the 2016 presidential election.

After two days of deliberation, the 12-member jury pronounced Trump guilty on all 34 counts.

Justice Juan Merchan set sentencing for July 11, days before the Republican Party is expected to nominate Trump for president ahead of the November 5 election.

Trump faces a maximum sentence of four years in prison, though the consensus is he is more likely to get a fine.

Being in jail would not prevent him from campaigning – nor from taking office if he beats incumbent Joe Biden in the November election.

Merchan thanked the jurors for their service and told them they were free to speak about their experience if they wished.

“Nobody can make you do anything you don’t want to do. The choice is yours,” Merchan said.

The verdict plunges the US into unexplored territory ahead of the November vote, when Trump will try to win back the White House.

Trump, 77, has denied wrongdoing and is widely expected to appeal.

“This was a disgrace,” Trump said afterwards as he proclaimed his innocence and repeated his complaints that the trial was rigged.

“The real verdict is going to be November 5 by the people,” he said.

Ivanka Trump’s message after the verdict. Source: Instagram

Trump gave a thumbs-up sign through the tinted window of his SUV as his motorcade left the courthouse.

Opinion polls show Trump and Biden, 81, locked in a tight race, and Reuters/Ipsos polling has found that a guilty verdict could cost Trump some support among independent and Republican voters.

The jury found Trump guilty of falsifying business documents after sitting through a five-week courtroom presentation that featured explicit testimony from porn star Stormy Daniels about a sexual encounter she says she had with Trump in 2006 while he was married to his current wife Melania. Trump denies ever having sex with Daniels.

Trump’s former fixer Michael Cohen testified that Trump approved a $US130,000 ($A196,000) hush money payment to Daniels in the final weeks of the 2016 election, when he faced multiple accusations of sexual misbehaviour.

The relatively short amount of time jurors took to reach a verdict was a sign that they thought there was enough evidence to back up Cohen’s testimony, said George Grasso, a retired New York judge who attended the trial.

Biden’s campaign said the verdict showed that no one was above the law and urged voters to reject Trump in the election.

“There is still only one way to keep Donald Trump out of the Oval Office: At the ballot box,” the campaign said in a statement.

The White House declined to comment.

Falsifying business documents is normally a misdemeanour in New York, but prosecutors in Manhattan District Attorney Alvin Bragg’s office elevated it to a felony on grounds that Trump was concealing an illegal campaign contribution.

“Our job is to follow the facts and the law without fear or favour, and that’s exactly what we did here,” Bragg said after the verdict.

He said there were “many voices out there, [but] the only voice that matters is the voice of the jury”.

Trump had complained that he could not get a fair trial in his heavily Democratic hometown.

This case was also likely to be the only one to go to trial before the election, as the others are delayed by procedural challenges.

-with AAP