1,941 U.S. military members lost

Violence in western Iraq has killed five U.S. troops: including four soldiers and a Marine.

The military says the Marine was killed by a roadside bomb Monday near the Syrian border. It's the first announced U.S. death in Operation Iron Fist, a major sweep that began over the weekend.

Three soldiers assigned to the same unit as the Marine were killed by another roadside bomb while conducting combat operations in another town where a second major offensive started Tuesday.

The military also said it's investigating the fatal shooting of a soldier Monday near Fallujah, about 40 miles west of Baghdad. [Mourning Marines]