MAP 24.2 The Korean War, 1950–1953 Considered a “police action” by the United Nations, the Korean War cost the lives of nearly 37,000 U.S. troops. Approximately 1 million Koreans were killed, wounded, or missing. Each side pushed deep into enemy territory, but neither could achieve victory. When hostilities ceased in 1953, a demilitarized zone near the original boundary line separated North and South Korea.