Sen. Hillary Clinton (D-N.Y.) denied any knowledge about a controversial picture of Sen. Barack Obama (D-Ill.) during a Democratic debate Tuesday night. The photo shows Obama during a 2006 trip to Kenya in which he dressed in traditional Kenyan garb. Some say the photo implies Obama is a Muslim. The Drudge Report had stated Clinton staffers had actually been circulating the photo.

"I certainly know nothing about it, and have made clear that is not the kind of behavior I condone or expect from the people working on my campaign," said Clinton.

Obama replied that he would take the senator on her word and wanted the issue put aside.

Clinton has seen the roles reversed in the campaign. She was once the front-runner, but is now considered the underdog.

The two sparred over health care, the war in Iraq and trade, particularly NAFTA. Clinton tried to score points by criticizing Obama for not directly rejecting support from the controversial Nation of Islam leader Louis Farrakhan, who has made anti-Semitic statements. Clinton pointed out that there is a difference between denouncing and rejecting.

?I'm happy to concede the point and I would reject and denounce,? said Obama concerning Farrakhan.

With crucial presidential primaries just one week away, Clinton needs big wins in the face of 11 successive Obama victories and an increasing stable of delegates for the Illinois senator.AP wire reports contributed to this story.