During Vietnam war, ARVN Mobile Guerrilla Forces (MGF) was US Special Forces trained and led unit created in the fall of 1966 during refinement and amplification of the mobile strike concept. These guerrilla units were organized, trained, and equipped to operate in remote areas previously considered to be Viet Cong or North Vietnamese Army havens. Once in the area of operations, the unit became a true guerrilla force in every respect except that of living solely off the land. Selected items of resupply were delivered by air. The guerrilla force operated from mobile bases, and the troops were capable of remaining and operating in a particular area for thirty to sixty days.