Updated

A homicide bombing killed six people Sunday in Iraq's Anbar province, but the target of the attack, a U.S.-backed Sunni tribal sheik, was unhurt, police said.

The bomber detonated his explosives belt after four guards stopped him at a checkpoint leading to the sheik's farm near Fallujah. The attack killed the four guards and two civilians and wounded four others, according to a police official, who spoke on condition of anonymity because he feared reprisals.

The sheik, Aeifan al-Issawi, is a leading member of the Anbar Awakening Council, a Sunni group that has turned against Al Qaeda in Iraq.

The U.S. military has credited the emergence of awakening councils with playing a major part in the decline in violence nationwide over the past six months. Such groups, backed by the Americans, have also managed to expel Al Qaeda from much of Anbar, a largely desert province in western Iraq.