PALM BEACH, United States, April 5, 2023 (BSS/AFP) - Donald Trump offered a full-throated defense of his conduct Tuesday in his first public remarks since being charged over hush money payments to a porn star, blasting the criminal prosecution as "an insult to our country."

Hours earlier the 76-year-old former US president pleaded not guilty to 34 felony counts in a dramatic hearing in New York that transfixed the nation -- and began the countdown to the first ever criminal trial of an American president.

"I never thought anything like this could happen in America -- never thought it could happen," Trump told an audience of several hundred donors, political allies and other supporters after returning to Mar-a-Lago, his beachfront mansion in southern Florida.

"The only crime that I've committed is to fearlessly defend our nation from those who seek to destroy it... It's an insult to our country."

Trump -- the frontrunner in the race for the 2024 Republican nomination -- said from a stage festooned with American flags in an opulent gold-and-cream ballroom that "radical left" prosecutors were out to get him "at any cost."

The bizarrely celebratory mood in the room seemed at odds with the gravity of the day's events in Manhattan, with Trump reprising the applause lines that his supporters hear regularly at his rallies -- and being rewarded with the same boisterous cheers and clapping.

Manhattan District Attorney Alvin Bragg is prosecuting Trump for cooking his company's books to hide payments he arranged for adult film actress Stormy Daniels days before the 2016 election, to cover up an alleged sexual encounter a decade earlier.

Trump's former chief financial officer Allen Weisselberg is serving a five-month jail term for the same charge of falsifying business records.

- 'Darkest hours' -

Manhattan prosecutors say Trump "repeatedly and fraudulently falsified New York business records to conceal criminal conduct that hid damaging information from the voting public during the 2016 presidential election."

A "statement of facts" released alongside the indictment included details of hush money payments to Daniels, Playboy model Karen McDougal and a former Trump Tower doorman claiming to have a story about a child Trump had out of wedlock.

Daniels was paid $130,000 by former Trump lawyer Michael Cohen, while McDougal and the doorman got $150,000 and $30,000 respectively from AMI, the publishers of supermarket tabloid the National Enquirer.

Bragg alleges that Trump and his allies "also took steps that mischaracterized, for tax purposes, the true nature of the payments."

Trump and his lawyers have accused Bragg of over-reaching in his characterization of the alleged misconduct.

The one-time reality TV star had sent a fundraising email even before flying back to Florida, saying that since the news of his indictment broke, his campaign had raised over $10 million.

"While we are living through the darkest hours of American history, I can say that at least for this moment right now, I am in great spirits," Trump said.

The twice-impeached Republican is the first sitting or former American president to be criminally indicted.

Earlier in the Manhattan courtroom, he answered "not guilty" to all charges in a clear voice, sitting with hunched shoulders and at times looking annoyed but mostly listening cooperatively.

- 'Election interference' -

Judge Juan Merchan said a trial could potentially start as soon as January -- a month before the presidential primaries kick off -- although Trump's lawyers have indicated they would want it pushed back to next spring.

In a spectacle that played out on live television -- with rival protesters rallying outside -- the hearing marked a watershed moment for the US criminal and political system.

A crowd of hundreds had gathered, with pro-Trump protesters -- sporting "MAGA" hats and attire emblazoned with the American flag -- yelling slurs at their opponents.

Trump for years rejoiced in his reputation as a playboy but has always denied the tryst with Daniels, which would have occurred just after his third wife Melania gave birth.

In a rambling, conspiracy theory laden tirade to his supporters, he described Merchan as a "Trump-hating judge" and denounced Bragg for what he called "massive election interference at a scale never seen before in our country."

But he spent much of his speech mocking several more serious investigations he faces, repeating previously-debunked allegations about being treated differently from previous presidents.

They include his efforts to overturn his 2020 election loss in the state of Georgia, his alleged mishandling of classified documents taken from the White House and his involvement in the storming of the US Capitol on January 6, 2021.