The Tripartite Pact—between the three Axis powers of Germany, Japan and Italy—guaranteed mutual support, and this paid off for Japan in July 1941 when French weakness in the wake of the fall of France to Germany allowed Japan to occupy French Indo-China (now modern Vietnam, Laos and Cambodia). This blocked a supply route for the Kuomintang, against whom Japan had been fighting since 1937, the Second Sino-Japanese War. It also gave Imperial Japan a seaboard facing Sarawak and North Borneo across the China Sea. In December 1941, Japan attacked US possessions in Hawaii and the Philippines, declaring war on the US and finally precipitating Germany's official declaration of war on America, according to the Pact.