Assailants in Iraq killed three U.S. servicemen, one in the capital and two in the south of the troubled country, the U.S. command said Saturday. Two Marines from the 11th Marine Expeditionary Unit were killed on Friday "as a result of enemy action" in Najaf province, south of the capital, the military said in a statement. In western Baghdad, an insurgent fired a rocket-propelled grenade at a patrolling U.S. vehicle, killing one soldier, the military said. The names of those killed were withheld pending notification of next of kin.