On December 7, 1941, Japan launched a surprise attack on the U.S. naval base at Pearl Harbor, Hawaii. The Japanese aimed to severely damage the U.S. Pacific fleet to prevent American interference with Japanese expansion in Southeast Asia. Over 2,300 Americans were killed and many ships and aircraft were destroyed in the hours-long assault. The attack drew the United States into World War II and led to declarations of war against Japan by the U.S. and its allies.