On December 7, 1941, Japanese planes raided the U.S. Naval Base Pearl Harbor in Hawaii. The massive surprise attack thrusted America into World War II. Following the attack, government suspicion arose around Americans of Japanese descent. A few months later, on March 29, 1942, Lieutenant General John L. DeWitt of the Western Defense Command issued Public Proclamation No. 4, which forced the evacuation and detention of West Coast residents of Japanese American ancestry. Approximately 120,000 Japanese Americans were sent to concentration camps in the United States between 1942 and 1945.