The North Korean army invaded South Korea on June 25, 1950, crossing the 38th parallel, which was the border between the two countries. General Douglas MacArthur counterattacked by landing Marines at Inchon, and cutting the supply lines to the North Korean forces surrounding the Pusan Perimeter. The North Korean army retreated out of South Korea. U.S. and United Nations forces followed them into North Korea and pushed the North Korean army all the way to the Chinese border. The Chinese army counterattacked. The U.S. and United Nations forces were pushed back by the Chinese and North Korean forces into a stalemate. The North Koreans and Chinese on one side and the United Nations, represented by U.S. officials on the other, negotiated from October 25, 1951, to June 27, 1953 finally signing the Korean Armistice Agreement on June 27th. The war had lasted from 1950-1953.