On 7 December 1941, Japanese forces attacked the United States Pacific Fleet at Naval Station Pearl Harbor, incorporated territory of Hawaii. The attack killed almost 2,500 people and crippled much of the U.S. battleship fleet, precipitating an open and formal state of war between the two nations the next day. The initial goals of Japanese leaders were to neutralize the U.S. Navy, seize possessions rich in natural resources, and establish strategic military bases to defend Japan's empire in the Pacific Ocean and Asia. To further those goals, Japanese forces captured the Philippines, Thailand, Malaya, Singapore, Burma, the Dutch East Indies, Wake Island, Gilbert Islands, New Britain and Guam. Joining the U.S. in the war against Japan were the rest of the Allied powers, several of whom, including the United Kingdom, Australia, and the Netherlands, had also been attacked by Japan.