During the Korean War, Seoul changed hands between the Soviet/Chinese-backed North Korean forces and the American-backed South Korean forces several times, leaving the city heavily damaged after the war. The capital was temporarily relocated to Busan. One estimate of the extensive damage states that after the war, at least 191,000 buildings, 55,000 houses, and 1,000 factories lay in ruins. In addition, a flood of refugees had entered Seoul during the war, swelling the population of the city and its metropolitan area to an estimated 1.5 million by 1955.