After the outbreak of the Pacific War, China became one of the Allies of World War II. In the Second Sino-Japanese War, China attempted to use this influence to assert Allied recognition of the KPG. However, the United States was skeptical of Korean unity and readiness for independence, preferring an international trusteeship-like solution for the Korean Peninsula. Although China achieved agreement by the Allies on eventual Korean independence in the Cairo Declaration of 1943, continued disagreement and ambiguity about the postwar Korean government lasted until the Soviet–Japanese War created a "de facto" division of Korea into Soviet and American zones, prompting the Korean War.