The initial assault by North Korean KPA forces were aided by the use of Soviet T-34-85 tanks. A North Korean tank corps equipped with about 120 T-34s spearheaded the invasion. These drove against a ROK Army with few anti-tank weapons adequate to deal with the Soviet T-34s. Additional Soviet armor was added as the offensive progressed. The North Korean tanks had a good deal of early successes against South Korean infantry, elements of the 24th Infantry Division, and those United States built M24 Chaffee light tanks that they encountered. Interdiction by ground attack aircraft was the only means of slowing the advancing Korean armor. The tide turned in favour of the United Nations forces in August 1950 when the North Koreans suffered major tank losses during a series of battles in which the UN forces brought heavier equipment to bear, including M4A3 Sherman medium tanks backed by U.S. M26 heavy tanks, along with the British Centurion, Churchill, and Cromwell tanks.