On 13 May 1953, 20 F-84s of the 58th Fighter Bomber Wing attacked the Toksan Dam, producing a flood that destroyed seven hundred buildings in Pyongyang and thousands of acres of rice. On 15–16 May, two groups of F-84s attacked the Chasan Dam.[28] The flood from the destruction of the Toksan dam "scooped clean" 27 miles (43 km) of river valley. The attacks were followed by the bombing of the Kuwonga Dam, the Namsi Dam and the Taechon Dam.[29][30] The bombing of these five dams and ensuing floods threatened several million North Koreans with starvation; according to Charles K. Armstrong, "only emergency assistance from China, the USSR, and other socialist countries prevented widespread famine."[4]