A former model has alleged that she was sexually assaulted by Donald Trump at the U.S. Open tennis tournament more than two decades ago. This has been denied by Trump's re-election campaign.

Amy Dorris stated that Trump, then a 51-year-old real estate developer, violated her outside a bathroom in his VIP box at the tournament in 1997, British newspaper The Guardian reported on Thursday. 

Dorris was 24 at the time and both her and her boyfriend were invited by Trump to join him in the VIP box, the newspaper said.

"He just shoved his tongue down my throat and I was pushing him off. And then that's when his grip became tighter and his hands were very gropey and all over my butt, my breasts, my back, everything," the newspaper quoted Dorris as saying. 

"I was in his grip, and I couldn't get out of it. I don't know what you call that when you're sticking your tongue just down someone's throat. But I pushed it out with my teeth. I was pushing it. And I think I might have hurt his tongue," she added.

Trump has faced a number of allegations of sexual misconduct prior to his time in office. Shortly before the November 2016 election an "Access Hollywood" recording from 2005 revealed him boasting about groping women. Trump dismissed the comments as "locker room banter" and apologized.

Dorris, a mother of twins, told the newspaper she considered coming forward in 2016 but decided against doing so partly out of fears for her family.

"Now I feel like my girls are about to turn 13 years old and I want them to know that you don't let anybody do anything to you that you don't want," she said.

The newspaper published photos that it said were provided by Dorris showing her with Trump and said that it interviewed several people who Dorris confided in at the time of the incident. It said that in total she provided six photos showing the two together as well as her ticket to the tournament on the day she said the incident occurred.

Following the report on Thursday, the Trump campaign denied Dorris' account in some of the strongest terms.

"The allegations are totally false," Jenna Ellis, a legal adviser to the Trump campaign, said in a statement. "We will consider every legal means available to hold The Guardian accountable for its malicious publication of this unsubstantiated story. This is just another pathetic attempt to attack President Trump right before the election."

The Guardian said in an email it stood by its reporting.

(With input from agencies)