Hillary Clinton's presidential campaign hit back furiously on Tuesday after standing accused of trying to smear rival Barack Obama by circulating a photograph of him in traditional African dress.

"Enough. If Barack Obama's campaign wants to suggest that a photo of him wearing traditional Somali clothing is divisive, they should be ashamed," Clinton's campaign manager Maggie Williams said in a statement.

Obama's campaign had accused the Clinton camp of "fear-mongering" after the picture of Obama in an African robe and turban appeared on gossip website Drudge Report, which said it had been distributed among Clinton aides.

"Hillary Clinton has worn the traditional clothing of countries she has visited and had those photos published widely," Williams said.

"This is nothing more than an obvious and transparent attempt to distract from the serious issues confronting our country today and to attempt to create the very divisions they claim to decry. We will not be distracted."

The Obama camp's anger over the photograph threatened to overshadow what Clinton billed as a "major address" in Washington on foreign policy, a week before make-or-break primaries in Ohio and Texas.

Obama campaign manager David Plouffe had issued a blistering statement accusing the Clinton campaign of underhand tactics over the picture of Obama, whose father was Kenyan, taken during a 2006 visit to Wajir, Kenya.

"On the very day that Senator Clinton is giving a speech about restoring respect for America in the world, her campaign has engaged in the most shameful, offensive fear-mongering we've seen from either party in this election," Plouffe said.

"This is... exactly the kind of divisive politics that turns away Americans of all parties and diminishes respect for America in the world," he said.

Asked if Clinton aides had circulated the picture, campaign communications chief Howard Wolfson said: "No, not to my knowledge.

"Obviously the campaign didn't sanction it," he told reporters.

"If you have any original reporting that the Clinton campaign circulated this picture, let me know. I've never seen that picture before. I'm not aware that anyone here has."