Stormy Daniels, the ex-porn star embroiled in the sex scandal behind Donald Trump's indictment, said in a UK newspaper interview published Friday that the criminal charges show he is "no longer untouchable".

Daniels, a 44-year-old former adult movie actress, told Britain's The Times that the indictment issued Thursday against the ex-president was "monumental and epic".

"I'm proud," Daniels said, in an interview the paper said was conducted from an undisclosed location in the United States.

"Trump is no longer untouchable," she said.

"The other side of it is that it's going to continue to divide people and bring them up in arms. He's already gotten away with inciting a riot, and causing death and destruction.

"Whatever the outcome is, it's going to cause violence, and there's going to be injuries and death," she warned.

Daniels, whose birth name is Stephanie Clifford, alleges she had sex with Trump in 2006, just months after his third wife, Melania, had given birth to their son Barron.

- 'Seen him naked' -

A New York grand jury indicted Trump over a $130,000 hush-money payment made to buy her silence during his 2016 presidential campaign.

The legal case relies on whether it counted as an illicit contribution to his campaign.

In predicting his indictment, Trump has called for protests and warned that it could lead to "potential death and destruction" for the country.

In her interview, Daniels admitted to being frightened "for the first time ever" over the long-running case, "because Trump himself is inciting violence and encouraging it".

She claimed that within hours of Thursday's indictment, threats of extreme violence and murder began arriving to her social media, email and phone.

"It just takes one crazy supporter who thinks they're doing God's work or protecting democracy," she added.

However, the one-time adult movie star revealed she would be willing to testify in court against Trump if asked, but noted that she had not been called to so far.

"I've seen him naked. There's no way he could be scarier with his clothes on.

"I'm not afraid, I have nothing to hide, and I look forward to telling everybody what I know."

The New York investigation is the first to reach a decision on charges, out of three major probes into the ex-president.

Daniels told The Times the indictment was a "vindication".

"But it's bittersweet. He's done so much worse that he should have been taken down (for) before."