WASHINGTON - Herman Cain, a Republican candidate for the 2012 presidential nomination, said Monday he had not sexually harassed women, rebuffing a report that he was accused by two women in the 1990s.

Cain, who has stunned the political establishment with his rise to the top of the polls, issued the denial in an interview on Fox News.

"I have never sexually harassed anyone," Cain told the conservative cable outlet.

He repeated his denial in an appearance at the National Press Club and said the story was a "witch hunt and that's what it is."

Cain -- a self-styled outsider relatively new to the national stage -- faces a new level of scrutiny after a burst of momentum in the race for the Republican presidential nomination. He's been steadily at or near the top of national surveys and polls in early presidential nominating states, competitive with former Massachusetts Gov. Mitt Romney.

"There's nothing else there to dig up," he declared at the National Press Club. "We have no idea the source of this witch hunt, which is really what it is."

In a later interview with The Associated Press, Cain was asked if he was unaware of the women's specific allegations, which date back to when he was head of the National Restaurant Association.

"Some of them," he responded.

When pressed, he said was not aware of any of the allegations.

"That was 12 years ago. So no, I don't remember," he said.

Earlier in the day, Cain acknowledged, "I do have a sense of humour and some people have a problem with that." In the interview with AP, Cain said that comment did not refer to the sexual harassment allegations.

"I was just referring to my natural sense of humour. So it was not related to that, OK?" he said.

Earlier Monday, Cain confirmed that he had been accused of sexual harassment but denied the allegations and said he was not involved in any payout.

In his denials to the report published on the website Politico, Cain said he did not know how the restaurant group had responded to the allegations.

"Yes, I was falsely accused while I was at the National Restaurant Association," he said.

Politico reported there was a settlement that amounted to five figures to the women.

"If there was a settlement, it was handled by some other officers at the National Restaurant Association," he said, adding that he hoped it would have been minimal because the accusations were false.

The report said the women signed agreements with the restaurant group that gave them five-figure financial payouts to leave the association and barred them from discussing their departures. Neither woman was identified.

The report was based on anonymous sources and, in one case, what the publication said was a review of documentation that described the allegations and the resolution.

Despite the embarrassing report, Cain continued with several planned appearances in Washington. He discussed his tax plan at the American Enterprise Institute, was to appear at the National Press Club and hold a health care briefing on Capitol Hill.

At the Press Club, in response to a question about race, Cain --an African American like President Barack Obama -- said he didn't think the president's current low approval rating had to do with racial prejudice.

"I don't think people being uncomfortable with this president has anything to do with race. They are uncomfortable with bad policy," he said, moving on to accuse the Obama administration and "its surrogates of playing the race card and the class warfare card."

Cain said he did not feel the burden of racism in his candidacy. "This many white people can't pretend that they like me." he said.

The former pizza company executive has been pointing to his long record in business to argue that he has the credentials needed to be president during a time of economic strife.

In its report, Politico said it confronted Cain early Sunday outside of the CBS News Washington bureau, where he had just been interviewed on "Face the Nation."

"I am not going to comment on that," he told Politico when asked specifically about one of the woman's claims.

When asked if he had ever been accused of harassment by a woman, he responded, Politico said, by asking the reporter, "Have you ever been accused of sexual harassment?"

A message seeking comment from Peter Kilgore, listed on the National Restaurant Association website as its chief legal counsel, was not immediately returned.