In the north, PLAF sappers attacked the South Vietnamese I Corps headquarters at Da Nang, but were beaten back by ARVN units and very close bombing strikes from American warplanes. Quang Tri was also attacked. In II CTZ, the battle for Nha Trang lasted almost twelve hours before ARVN and Army Ranger units defeated enemy forces. At Qui Nhon in the Central Highlands, ARVN intelligence actually knew of attack plans from captured Viet Cong agents. Nonetheless, the attackers were able to seize numerous objectives, at least temporarily. At Ban Me Thuot, the fighting raged for nine days with the city center changing hands at least four times during the battle. The ARVN commander at Ban Me Thuot, Colonel Dao Quang An, had cancelled holiday leaves and sent out preemptive ambush patrols based upon intelligence from captured NLF agents. The American advisor to Colonel An’s command praised the colonel for his tactical leadership in the battle.