The Republic of China had been fighting Japan intermittently since the 1931 Mukden Incident, when Japan annexed Manchuria. On 7 July 1937, the Marco Polo Bridge Incident led the two countries to full-scale war. With this and civil conflict between the Kuomintang (KMT, Chinese Nationalist Party) and the Communist Party of China, the Chinese Nationalist Government's full attention was within its borders. However, Generalissimo Chiang Kai-shek still managed to send troops to Britain's aid in Burma, in early 1942. More than 1.5 million Japanese military personnel were bogged down in China with casualties estimated at 1.1–1.9  million. At the start of the war, the Chinese army had 2.6 million soldiers; by end of the war it had grown to 5.7 million (excluding communist soldiers).