“There’s not anybody in my campaign that knew anything about this, that’s associated with my campaign, in any form or fashion, end of story. This is one of those things that’s about as clear cut as I can tell you,” Perry told conservative website RedState.com late on Wednesday.

Cain has been accused by at least three woman of sexual harassment when he was head of the National Restaurant Association in the mid-1990s. The issue has been front and center in recent days in the race for the 2012 Republican presidential nomination to face President Barack Obama, a Democrat, in the November 2012 election.

Cain, who is leading polls of Republican voters two months before voting in the nomination process starts, has blamed both the news media and the Perry campaign for spreading information about the case in order to undercut his upstart campaign.

Political commentators say Perry stands to benefit from a collapse of Cain’s campaign in their fight to become the conservative alternative to the more moderate Mitt Romney.

At the same time, most analysts believe Cain would eventually stumble anyway, as the former pizza executive has little political experience and has recently suffered a series of stumbles.

But the 65-year-old businessman has surged ahead of Romney or even with him in national polls and in Iowa, the state that holds the first US nominating contest of 2012 on Jan. 3.

An extended controversy over Cain may help no one in the Republican race to find a challenger to Obama, whose slide in the polls has stopped and who may be gaining traction with his criticism of Republican lawmakers for blocking his jobs legislation.

“While hurling unfounded accusations may serve as a temporary distraction from Mr. Cain’s mounting troubles, we hope we can all get on with the serious business of selecting the best candidate to defeat Barack Obama,” Perry spokesman Ray Sullivan said.

The Cain controversy has spread through both the Perry camp as well as that of former Massachusetts Governor Romney, who Perry aides in turn suggested was behind the leak. Romney’s campaign said this was not true.

Cain told Forbes magazine he believes a former employee who now works for Perry, Curt Anderson, was the original source of the story published by news website Politico on Sunday that reported on the harassment charges.

Anderson denied it, saying: “I have great respect for Herman and his character and I would never speak ill of him, on the record or off the record.”

Joel Bennett, a lawyer for one of the women who have made accusations against Cain, said his client had decided not to go public or make a public statement in order to shield herself from a media frenzy.

Bennett said in an e-mail that he would send a draft statement of his client’s position to the National Restaurant Association on Thursday, seeking approval for the statement to be released despite the woman’s confidentiality agreement.

Bennett had earlier said his client wanted to be released from a confidentiality agreement that has barred her from speaking about her interaction with Cain.