 While diversionary attacks were launched in other areas, Giáp ordered his men to covertly position their artillery by hand.Defying standard military practice, he had his twenty-four 105mm howitzers placed on the forward slopes of the hills around Dien Bien Phu, in deep, mostly hand-dug emplacements protecting them from French aircraft and counter-battery fire.With anti-aircraft guns supplied by the Soviet Union, Giáp was able to severely restrict the ability of the French to supply their garrison, forcing them to drop supplies inaccurately from high altitude.