Japanese aggression against China, evidenced by the move into Manchuria in 1931 and subsequent incidents in Shanghai, surfaced anew in 1937 when a minor clash near Peking erupted into a full-scale invasion.
The area of hostilities spread quickly, and units of the U.S. Asiatic Fleet, under Admiral Harry E. Yarnell, evacuated American citizens and protected national interests, standing firm again Japan's increasingly belligerent actions toward neutrals. At Shanghai, United States ships were endangered by Japanese aerial bombings and artillery fire.
On 12 December 1937, Japanese naval aircraft attacked and sank the river gunboat USS Panay. At the end of World War II, the U.S. Navy returned to China to repatriate Japanese soldiers and to assist the Chinese Central Government in enforcing the surrender terms. Seventh Fleet Amphibious Forces provided transport for Chinese Nationalist troops and carried food supplies from Shanghai up the Yangtze to fight near-famine conditions in the interior.