The Korean War began as a civil conflict between communist North Korea and the Republic of Korea to the south. After failed attempts to create insurgencies in South Korea, North Korean troops crossed the 38th parallel in the early hours of June 25, 1950, invaded South Korea, and captured Seoul. With support from the United Nations Security Council, U.S. President Harry Truman ordered General of the Army Douglas MacArthur to use whatever force was necessary to aid the South Koreans, marking the first time in the United Nations' short history that force was authorized in response to another country's aggression. United Nations countries participated throughout the war, and fighting ranged from the defense of the Pusan Perimeter and the Inchon landing to battles at Chosin Reservoir, Chipyong-Ni, Bloody Ridge, Heartbreak Ridge, Old Baldy, the Hook, T-Bone Hill, Pork Chop Hill, and the Kumsong River Salient. Chinese Communist troops entered the war after U.N. forces advanced into North Korea across the 38th parallel, and the conflict continued through major ground, air, and naval actions until an armistice was signed on July 27, 1953. General Taylor said the cease-fire was not the end of the war but a suspension of hostilities, and there has never been a formal peace treaty. Representatives of the U.N. and the Korean People's Army continue to meet in the Joint Security Area at Panmunjon, and an armistice designed to last 90 days has endured for over 50 years. United Nations forces reached a peak strength of 1.2 million and suffered 1.2 to 1.8 million casualties, while United States forces reached a peak strength of 480,000 and suffered 36,574 casualties, 103,284 wounded, 4,578 missing in action, and 7,245 prisoners of war.