Four US Marines were killed in fighting in Anbar province, and three were killed by a roadside bomb in northern Iraq, the military said Friday. The four Marines assigned to Multi National Force - West were killed Thursday while conducting combat operations in Anbar, a predominantly Sunni province west of Baghdad that has seen a recent drop in violence, according to a statement. Three Task Force Lightning soldiers also were killed Thursday when a bomb exploded near their vehicle in the northern Ninevah province, the military said separately.