Two women have told the New York Times that Donald Trump touched them inappropriately, but the Trump campaign has dismissed the report.
One woman said Mr Trump grabbed her breasts and attempted to put his hand up her skirt on a flight three decades ago.
The second woman said Mr Trump kissed her on the mouth against her will at Trump Towers in 2005.
Mr Trump's campaign said "this entire article is fiction".
The New York Times was launching "a completely false, coordinated character assassination," a statement from his campaign said.
Jessica Leeds, 74, from Manhattan, told the paper she had been sitting next to Mr Trump in the first-class cabin of a flight to New York when he lifted the armrest and began to touch her. She was 38 years old at the time.
"He was like an octopus... his hands were everywhere," she said. "It was an assault."
Rachel Crooks was a 22-year-old receptionist at a real estate company in Trump Tower when she said she was kissed on the lips by Mr Trump outside a lift in the building.
"It was so inappropriate," Ms Crooks told the New York Times.
"I was so upset that he thought I was so insignificant that he could do that."
Neither women has ever reported their accounts to the authorities, but both shared what happened to them with friends and family.
On Friday a 2005 video emerged which showed Mr Trump making obscene remarks about groping women.
He apologised for the comments, but described them as "locker-room talk".