A grand jury in New York voted to indict Trump over possible offences related to a $130,000 (£105,000) payment to Stormy Daniels during the 2016 presidential election campaign.

It was allegedly made in exchange for Daniels' silence about an alleged sexual encounter she said she had with Trump a decade earlier.

He is the first former US president to face criminal charges in court, even as he makes a bid to retake the White House in 2024.

Trump, a Republican, said he was "completely innocent" and called the indictment "political persecution", with his lawyers saying they will "vigorously fight" it.

Live updates: Prosecutors launch criminal case against Trump

The Manhattan district attorney's investigation centred on money paid to Daniels and former Playboy model Karen McDougal, whom he allegedly feared would go public with claims they had extramarital sexual encounters with him.

Federal prosecutors have said Trump's personal lawyer at the time, Michael Cohen, made the payment to Daniels at Trump's direction.

Cohen has said Trump directed hush money payments to Daniels, real name Stephanie Clifford, and also to McDougal.

Trump has denied having affairs with either woman.

He said: "The Democrats have lied, cheated and stolen in their obsession with trying to 'Get Trump,' but now they've done the unthinkable - indicting a completely innocent person in an act of blatant election interference."

"Never before in our Nation's history has this been done."

He added: "I believe this witch-hunt will backfire massively on Joe Biden."

Trump was expected to surrender to authorities next week, though the details were still being worked out, according to a person familiar with the matter.

Trump has denied any wrongdoing and has repeatedly attacked the investigation by district attorney, Alvin Bragg.

His office has spent nearly five years investigating Trump and the grand jury has been hearing its evidence since January.

Trump son hits out at indictment

On Twitter, one of Trump's sons, Eric, wrote: "This is third world prosecutorial misconduct. It is the opportunistic targeting of a political opponent in a campaign year."

Amid speculation in recent weeks that the former American leader was due to be indicted, Trump urged his supporters to protest against the authorities if he was detained.

He published a long statement describing the investigation as a "political witch-hunt trying to take down the leading candidate, by far, in the Republican Party".

"I did absolutely nothing wrong," he said, before criticising a "corrupt, depraved and weaponised justice system".

Other ongoing cases Trump faces include a Georgia election interference probe and two federal investigations into his role in the 6 January 2001 insurrection at the US Capitol.