The Republican candidate said he "never met" the women who accused him
Donald Trump has gone on the attack after a series of accusations were levelled against him that he made unwanted advances on women.
US First Lady Michelle Obama has slammed Mr Trump's treatment of women, saying that his "obscene" comments had shaken her "to my core".
The Republican presidential candidate said on Thursday evening that he had "never met" the women who accused him of sexual assault and advances.
He told supporters in Ohio the accusations were "outright lies," and what had been described "had never happened".
He claimed the media had "slandered and lied about me" after earlier accusing the press of conspiring with Hillary Clinton against his White House bid.
His running mate Mike Pence also blamed the media and Mrs Clinton for what he described as "a discussion of slander and lies".
It came as Mr Trump's wife Melania called portions of a People magazine story alleging a sexual assault by her husband "false and completely fictionalised" and threatened to sue.
In his last rally of the day in Cincinnati, Mr Trump made no mention of the allegations as the crowd cheered wildly and booed reporters covering the event.
Criticism of Mr Trump started after a clip emerged, from 2005, in which the mogul brags about women letting him kiss and grope them because he is famous, saying "when you're a star they let you do it".
Mr Trump said he was sorry "if anyone was offended" by the "locker room banter".
But more allegations have emerged in recent days, with footage from 1992 featuring Mr Trump telling a young girl he would be dating her in 10 years.
Two other women say he touched them inappropriately.
Mrs Obama, speaking at a Mrs Clinton rally in New Hampshire, said the Republican's sexual comments should not be seen as "politics as usual", adding that they were not simply "lewd comments" and not just "locker room banter".
She continued: "This was a powerful individual speaking freely and openly about sexually predatory behaviour."
Mrs Obama said his behaviour sent a dangerous message to children and told the rally that the measure of any society is "how it treats its women and girls".
Saying it is not how someone who wants to be President behaves, she added that "strong men, men who are truly role models, do not need to put down women to make themselves feel powerful".
Her husband, Barack Obama, later said Republicans who appeared to be abandoning Mr Trump's bid for the White House don't deserve any credit for distancing themselves as they had stayed silent for too long.
Mr Trump offered no evidence discrediting the new reports except to ask why his accusers had waited years and then made their allegations less than a month before the election.