Unable to neutralize U.S. opposition to its actions in SE Asia, Japan opened hostilities against the United States and Great Britain on December 7, 1941, by striking at Pearl Harbor, Singapore, and other Pacific possessions. The fortunes of war at first ran in favor of Japan, and by the end of 1942 the spread of Japanese military might over the Pacific to the doors of India and of Alaska was prodigious. Then the tide turned; territory was lost to the Allies island by island; warfare reached Japan itself with intensive bombing; and finally in 1945, following the explosion of atomic bombs by the United States over Hiroshima and Nagasaki, Japan surrendered on August 14, the formal surrender being on the U.S. battleship Missouri in Tokyo Harbor on September 2, 1945.