Republicans have accused Manhattan District Attorney Alvin Bragg of waging a "politically motivated prosecution" of former President Donald Trump.

Bragg is investigating a $130,000 payment to pornographic actress Stormy Daniels in the weeks leading up to the 2016 presidential election.

The payment was allegedly made to stop her from going public about a liaison she says she had with Trump years earlier.

Trump's ex-lawyer-turned-adversary Michael Cohen, who has testified before the grand jury, says he made the payment on his then boss's behalf and was later reimbursed.

If not properly accounted for, the payment could result in a misdemeanor charge for falsifying business records, experts say.

That might be raised to a felony if the false accounting was intended to cover up a second crime, such as a campaign finance violation, which is punishable by up to four years behind bars.

Trump insists he is innocent, and has escalated his attacks on Bragg in recent days. Early Friday morning, the former president warned of "death & destruction" if he were to be charged with a crime.

With additional reporting by AFP