US Republican presidential candidate Donald Trump faced a fresh allegation of groping today, even as his running mate promised that evidence casting doubt on other accusations of sexual misconduct would be made public soon.

The Washington Post published an interview with a woman who said Trump put his hand up her skirt in a crowded New York nightclub in the early 1990s in an unwanted advance.

"He did touch my vagina through my underwear, absolutely," Kristin Anderson said in a video interview on the newspaper's website. "It wasn't a sexual come-on. I don't know why he did it. It was like just to prove that he could do it," she told the paper.

Anderson could not immediately be reached for comment. Trump spokespeople did not immediately respond to requests for comment.

The Post reported that Trump spokeswoman Hope Hicks said the candidate "strongly denies this phoney allegation by someone looking to get some free publicity. It is totally ridiculous."

Trump's White House campaign has been scrambling to recover from the release a week ago of a 2005 video in which he bragged about groping women and making unwanted sexual advances. While Trump said the video

While Trump said the video was just talk and he had never behaved in this way, multiple women subsequently went public with allegations of sexual misconduct against the New York real estate magnate going back three decades.

Trump furiously denied the allegations, saying that the New York Times, which published two women's claims, and other media, along with his Democratic rival Hillary Clinton, were engaged in a vicious campaign to stop him from winning the November 8 election.

Republican vice presidential candidate Mike Pence vigorously defended Trump. "Stay tuned. I know there's more information that's going to be coming out that will back his claim that this is all categorically false," Pence told CBS show "This Morning."

Trump was scheduled to address a rally in Greensboro, North Carolina later today.

In Los Angeles, celebrity attorney Gloria Allred planned a news conference on Friday afternoon with a woman she said will accuse Trump of victimising her.

DISPUTES WITH MEXICO

The Wall Street Journal reported that Trump would accuse Mexican billionaire Carlos Slim - the top shareholder in the New York Times Company - of helping to generate reports of the sexual misconduct.

The Times reported on Wednesday that two women said they had endured unwanted groping or kisses from the former TV personality. Several other women made allegations of sexual aggression by Trump in various media outlets following that report.

Trump is expected to blame Mexican billionaire and NYT shareholder Carlos Slim for the leaked allegations. Photo: Reuters

Reuters could not independently verify the incidents. The Times yesterday said it stood by its story and rejected charges the article was libellous, after a lawyer for Trump threatened legal action and demanded a retraction.

Trump will claim that Slim, as a donor to the Clinton Foundation charity who also holds a 17.35 per cent stake in the New York Times, has an interest in helping her White House campaign, the Wall Street Journal said, citing a campaign adviser.

His allegations would feed into Trump's claims of a rigged election system and "false smears" that he says are part of a conspiracy bent on defeating him.

If Trump goes on the offensive against Slim it will only be the latest chapter in a running series of skirmishes with Mexico and Mexicans.

Trump kicked off his campaign last year accusing Mexico of sending rapists and drug dealers to the United States and promised to build a wall along the southern US border that he said he would make Mexico pay for.

He also pledged to tear up or revise the North American Free Trade Agreement. The Mexican peso slid to record lows in September when Trump was close to Clinton in opinion polls, but the currency has since climbed back.

Shortly after Trump's comments insulting Mexicans last year, a television company controlled by Slim cancelled a project with Trump. "His statement was totally out of line ... working with someone so closed-minded was not going to work," Arturo Elias, Slim's spokesman and son-in-law, said at the time.

Trump has previously linked Slim to the New York Times' coverage of his campaign.

"I know why I get bad treatment in the New York Times. Because it's owned by Mexico," Trump said at a February rally in Nevada. "I don't know if you know, a rich guy in Mexico actually has power at the New York Times. I wonder why they don't like us, you know, I just wonder," he said.

Elias said Slim had "absolutely no contact" with the newspaper's reporters or editors on their Trump campaign coverage and "zero" contact with the paper's news operations.

"Slim does not know Trump and he certainly is not interested in what happens in his personal life," Elias said.

The Trump campaign did not immediately respond to Reuters' requests for comment on the Journal report.

New York Times publisher Arthur Sulzberger Jr. said in a statement, "Carlos Slim is an excellent shareholder who fully respects boundaries regarding the independence of our journalism. He has never sought to influence what we report."