Donald Trump launched into attacks on the judge in his criminal trial and continued to undermine New York’s criminal justice system on Friday, as he tried to repackage his conviction on 34 felony charges as fuel, not an impediment, to his latest White House bid.

Former US president Mr Trump spoke to reporters at his namesake tower in Manhattan on Friday, his return to campaigning a day after he was convicted of trying to illegally influence the 2016 election by falsifying business records to hide a hush money payment to a porn actress who claimed they had sex.

Mr Trump, as defiant as ever, said the verdict was illegitimate and driven by politics and sought to downplay the allegations underlying the case.

“It’s not hush money. It’s a non-disclosure agreement, totally legal, totally common,” he said.

“If they can do this to me, they can do this to anyone,” Mr Trump said. “These are very bad people.”

No former president or presumptive party nominee has ever faced a felony conviction or the prospect of prison time, and Mr Trump is expected to keep his legal troubles central to his campaign.

He has long argued without evidence that the four indictments against him were orchestrated by Democratic President Joe Biden to try to keep him out of the White House.

“There is nobody who is more defiant,” said Trump spokesman Jason Miller on Fox News hours after the verdict was read.

“He’s ready to get out there and start fighting again.”

He chose to start Friday in the atrium of Trump Tower, the brass and rose marble lobby where he descended his golden escalator to announce his 2016 campaign nine years ago next month.

In his disjointed remarks, Mr Trump initially started attacking Mr Biden on immigration and tax policies before moving to his case, saying he was threatened with jail time if he violated a gag order.

He picked apart intricate parts of the case and trial proceedings, saying they  were unfair, making false statements and misrepresentations as he did so.

Mr Trump said he wanted to give evidence but said the judge wanted to go into every detail.

“I would have liked to have testified,” he said. “But you would have said something out of whack like ‘it was a beautiful sunny day’, and it was actually raining out.”

Mr Trump, who had the right to give evidence but did not, also tested the limits of the gag order that prohibits him from publicly criticising witnesses including Michael Cohen, calling his former fixer, the star witness in the case, “a sleazebag”.

His son Eric Trump and daughter-in-law Lara Trump joined him, but his wife, Melania Trump, who has been publicly silent since the verdict, was not seen.

Outside, on Manhattan’s Fifth Avenue, supporters gathered across the street were flying a giant red “Trump or death” sign that was flapping in front of a high-end boutique.

On Friday, his campaign announced it had raised 34.8 million dollars (£27.3 million) as donations poured in after the verdict.

That is more than one million for each felony charge and more than his political operation raised in January and February combined.

Mr Trump and his campaign had been preparing for a guilty verdict for days, even as they held out hope for a hung jury.

On Tuesday Mr Trump railed that not even Mother Teresa, the nun and saint, could beat the charges, which he repeatedly described as “rigged”.

His top aides on Wednesday released a memo in which they insisted a verdict would have no impact on the election, whether Mr Trump was convicted or acquitted.

The news nonetheless landed with a jolt. Mr Trump, his team and reporters at the court had been under the impression that the jury on Thursday would wrap up deliberations for the day at 4.30pm.

Mr Trump sat smiling and chatting with his lawyers as the proceedings seemed to be coming to a close.

He had spent the hours before the verdict was announced sequestered in the private courtroom where he had spent breaks throughout the trial, huddled with his lawyers and campaign aides.

As the jury was deciding his fate, he filled his time making calls, firing off social media missives and chatting with friends, including developer Steve Witkoff, who joined him in court, and North Dakota governor Doug Burgum, who is considered a top vice-presidential contender.

In a sign that they expected deliberations to continue, Mr Trump’s holding room was outfitted with a television on Thursday.

Instead, Judge Juan Merchan announced that a verdict had been reached. Thirty minutes later Mr Trump listened as the jury delivered a guilty verdict on every count. He sat stony-faced while the verdict was read.

His campaign fired off a flurry of fundraising appeals, and allies rallied to his side. One text message called him a “political prisoner”, even though he has not yet found out if he will be sentenced to prison.

The campaign also began selling black “Make America Great Again” caps to reflect a “dark day in history”.

Aides reported an immediate rush of contributions so intense that the platform the campaign uses for fundraising, crashed.

The millions raised on Thursday did not include what Mr Trump collected at his in-person fundraiser or any donations that continued to come in online on Friday.

“President Trump and our campaign are immensely grateful from this outpouring of support from patriots across our country,” Mr Trump’s senior campaign advisers Chris LaCivita and Susie Wiles said in a statement.

“President Trump is fighting to save our nation and November 5 is the day Americans will deliver the real verdict.”

Mr Trump has long complained that the trial limited his campaign appearances for several weeks. “I want to campaign,” he had told reporters on Thursday before a verdict was reached.

It is unclear, however, how much Mr Trump’s schedule will ramp up in the days ahead. He held only a handful of public campaign events as the trial unfolded, despite the fact that he had Wednesdays, as well as evenings and weekends, to do what he wished.

He will have his first debate with Mr Biden, announce a running mate and formally accept his party’s nomination at the Republican National Convention.

But he will have to return to court on July 11 for sentencing. He could face penalties ranging from a fine or probation, or up to four years in prison.