Japan launched a surprise attack on the Clark Air Base in Pampanga on December 8, 1941, just ten hours after the attack on Pearl Harbor. Aerial bombardment was followed by landings of ground troops on Luzon. The defending Philippine and United States troops were under the command of General Douglas MacArthur. Under the pressure of superior numbers, the defending forces withdrew to the Bataan Peninsula and to the island of Corregidor at the entrance to Manila Bay.