The Viet Minh assault began in earnest on 13 March 1954 with an attack on the northeastern outpost, "Béatrice", which was held by the 3rd Battalion, 13th Foreign Legion Demi-Brigade. Viet Minh artillery opened a fierce bombardment with two batteries each of 105mm howitzers, 120mm mortars, and 75mm mountain guns (plus seventeen 57mm recoilless rifles and numerous 60mm and 81/82mm mortars). French command was disrupted at 18:30 when a shell hit the French command post, killing the battalion commander, Major Paul Pégot, and most of his staff. A few minutes later, Lieutenant colonel Jules Gaucher, commander of the entire central subsector, was also killed by artillery fire. The Viet Minh 312th Division then launched an assault with its 141st and 209th Infantry Regiments, using sappers to breach the French obstacles.