U.S. Marines with 2nd Battalion, 3rd Marine Regiment, currently assigned to 4th Marines, 3rd Marine Division, III Marine Expeditionary Force, hold a security position during a tactical convoy training course March 6, 2014 at Convoy Live-Fire Exercise Range, Republic of Korea. After a simulated improvised explosive device detonated and "damaged" their Humvee, the Marines posted security while another Humvee prepared to tow the vehicle.