Kenyan elders demanded an apology from Washington on Thursday ahead of a planned protest over a controversial photo of U.S. presidential hopeful Barack Obama in traditional Somali dress.

The picture, which appeared on a U.S. Web site, showed the Democratic frontrunner donning a white headdress and robes during a visit in 2006 to the remote north-eastern town of Wajir.

The photo took centre stage in an increasingly acrimonious race for the White House, with Obama aides accusing his party rival Hillary Clinton's camp of the most shameful, offensive fear-mongering after it was published.

Obama, whose late father was from western Kenya, has fought a whispering campaign by fringe elements who wrongly say that he is Muslim and have even compared his surname to that of al Qaeda leader Osama bin Laden.

Clinton's campaign denied it officially approved the picture's release.

The dispute has angered many in Kenya, especially ethnic Somalis from the northeast, who resent the implication that Obama did anything wrong during his visit.

Wajir residents plan to demonstrate after Friday prayers to show their support for the Illinois senator.

Mohamed Ibrahim, who attended one of two crisis meetings held in Wajir on Thursday by clan members who hosted Obama on his trip, said Washington must immediately make amends to them and especially to the elder pictured with him.

The U.S. government must apologise to us as a clan and the old man, Ibrahim told Reuters by telephone. We have been offended and we cannot afford to just watch and stay silent.

He said it was essential Clinton clear her name too.

The old man in question was retired chief Sheikh Mohamed Hassan, a senior elder who deserved great respect, local residents said.

He was the right person to perform any such activity like dressing a visitor like Obama with traditional Somali clothes, said another Wajir community leader, Mukhtar Sheikh Nur.

We give special treatment and respect to any visitor.

If there was no apology, the elders said, they would demand the expulsion of U.S. troops based near Garissa town.

Many Kenyans support Obama in the way the Irish idolised U.S. President John F. Kennedy in the 1960s -- as one of their own who succeeded beyond their wildest dreams.

Following Obama's streak of 11 straight wins in the battle to become the Democratic nominee, Clinton needs to win next week in Ohio and Texas to keep her campaign alive.

Once the odds-on favourite to win the party's nomination to run against a Republican candidate in the general election, she has lost big leads in public opinion polls in the two states as Obama has gained momentum and made inroads among her supporters.