A former model has come forward to accuse Donald Trump of sexually assaulting her at the US Open tennis tournament more than two decades ago, in an alleged incident that left her feeling “sick” and “violated”.

In an exclusive interview with the Guardian, Amy Dorris alleged that Trump accosted her outside the bathroom in his VIP box at the tournament in New York on 5 September 1997.

Dorris, who was 24 at the time, accuses Trump of forcing his tongue down her throat, assaulting her all over her body and holding her in a grip she was unable to escape from.

“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.

“I was in his grip, and I couldn’t get out of it,” she said, adding: “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.”

Via his lawyers, Trump denied in the strongest possible terms having ever harassed, abused or behaved improperly toward Dorris.

Dorris, who lives in Florida, provided the Guardian with evidence to support her account of her encounters with Trump, including her ticket to the US Open and six photos showing her with the real estate magnate over several days in New York. Trump was 51 at the time and married to his second wife, Marla Maples.