Image copyright AFP Image caption Karena Virginia: "I felt intimidated and I felt powerless"

A tenth woman has come forward to accuse US presidential candidate Donald Trump of sexual assault.

Karena Virginia said Mr Trump approached her when she was waiting for a car outside the US Open tennis tournament in New York in 1998.

She accused the current Republican nominee of grabbing her breast and making objectifying statements about her to other men in his group.

Mr Trump's campaign dismissed the claim as a "fictional story".

"Discredited political operative Gloria Allred, in another coordinated, publicity seeking attack with the Clinton campaign, will stop at nothing to smear Mr. Trump. Give me a break," said Jessica Ditto, a Trump campaign spokeswoman.

"Voters are tired of these circus-like antics and reject these fictional stories and the clear efforts to benefit Hillary Clinton."

Mrs Virginia - a yoga teacher who comes from the New York area - said she expected to be personally attacked by Mr Trump, but felt it was her "duty as a woman, as a mother, a human being, and as an American citizen to speak out and tell the truth about what happened to me".

"Perhaps he will label me just another nasty woman", Mrs Virginia added.

Mr Trump, at the final televised presidential debate in Las Vegas, called his Democratic opponent Hillary Clinton "such a nasty woman".

Image copyright Getty Images Image caption "Such a nasty woman", Mr Trump said about his rival at the final debate in Las Vegas

Speaking at a press conference in Los Angeles alongside her lawyer Gloria Allred, Mrs Virginia recounted her alleged encounter with Mr Trump when she was 27 years old.

She said she was waiting for her hire car to arrive when Mr Trump approached her and made comments about her physical appearance to a group of men he was with.

"He said: 'Hey look at this one. We haven't seen her before,'" Mrs Virginia tearfully recounted, saying that his words described her "as though I was an object rather than a person".

"Then his hand touched the right inside of my breast. I was in shock. I flinched."

She told reporters that Mr Trump then said to her: "Don't you know who I am?"

"I felt intimidated and I felt powerless," she said, explaining that the incident left her feeling "ashamed" and that she blamed herself for many years.

Mrs Allred - who is a vocal supporter of Mrs Clinton - insisted that her legal office was not working in co-ordination with the Clinton campaign, and that Mrs Virginia had sought her help to announce the accusation.

She said that there were no corroborating witnesses to the incident, but that Mrs Virginia had recounted the story to friends soon after, and also later to her husband.