North Korea invaded the South on 25 June 1950, and swiftly overran most of the country. In September 1950 United Nations force, led by the USA, intervened to defend the South, and following the Incheon Landing and breakout from the Pusan Perimeter, rapidly advanced into North Korea. As the UN force neared the border with China, Chinese forces intervened on behalf of North Korea, shifting the balance of the war again. Fighting ended on 27 July 1953, with an armistice that approximately restored the original boundaries between North and South Korea.