President Donald Trump, himself a subject of multiple sex assault allegations, came out Friday on the side of his Democratic challenger Joe Biden, telling him to "fight" an accusation that he assaulted a woman three decades ago.

"I would just say to Joe Biden: just go out and fight it. It's, you know, it's one of those things," Trump said in interview with right-wing radio host Dan Bongino.

"You know, it's his problem, but I like to get in front of it and I just deny it. If it's not true, you deny it," Trump said.

"I've been a total victim of this nonsense false accusations."

The advice was Trump's first public comment since Biden broke his own silence on the controversy, telling a MSNBC television interview early Friday that the allegation of assault was "unequivocally" untrue.

"I don't know why after 27 years all of this gets raised," said Biden, who leads Trump in most polls ahead of the November election.

He is accused by Tara Reade, a former staffer when he was a senator, of pinning her against a wall and digitally penetrating her in 1993, when she was 29. 

Trump came into office in 2016 having brushed off more than a dozen accusations from women that over the years he committed everything from harassment to rape.

Shortly before the election, a tape recording emerged, dating from 2005, in which Trump was heard boasting about how his fame allowed him to "grab" women by the genitals when he wanted.

Trump dismissed this as "locker room banter" but subsequently apologized.

In his interview with Bongino, Trump echoed many conservatives in angrily comparing the relatively low-heat Biden controversy with the intense scandal that blew up around Trump's latest Supreme Court pick Brett Kavanaugh.

Kavanaugh's 2018 confirmation process was severely rocked by an accusation from Christine Blasey Ford that he had tried to rape her when they were teenagers in 1982.

Despite defending Biden, Trump stressed that he found the accuser more solid than in Kavanaugh's case -- a talking point that is widely shared in the Republican camp.

"I watched Tara and she seems very credible," Trump said, adding that he'd also listened to interviews in which the now deceased mother of Reade and others said they had heard her tell the story years ago.

"So, you know, I guess in a way you could say, I'm sticking up for him but the mother was very compelling certainly and the girlfriend or the friends were very compelling," Trump said.

"Certainly far more compelling than anything they had with respect to Brett Kavanaugh."

https://www.youtube.com/watch?v=pOavNaBX4NU