The USS Panay incident was a Japanese bombing attack on the U.S. Navy river gunboat Panay and three Standard Oil Company tankers on the Yangtze River near the Chinese capital of Nanjing on December 12, 1937. Japan and the United States were not at war at the time. The boats were part of the American naval operation called the Yangtze Patrol, which began following the joint British, French, and American victory in the Second Opium War.