Fighting began at Khe Sanh in late April 1967 with the hill fights, which later expanded into the 1968 Battle of Khe Sanh. U.S. commanders hoped that the PAVN would attempt to repeat their famous victory at the Battle of Dien Bien Phu, which would permit the U.S. to wield enormous air power. Boeing B-52 Stratofortresses alone dropped more than 75,000 tons of bombs on the PAVN 304th and 325th Divisions encroaching the combat base in trenches.