The attack on Pearl Harbor on 7 December 1941 brought the United States into the war, but with eight battleships sunk or damaged by air attack. On 10 December 1941 HMS "Prince of Wales" and the battlecruiser were sunk by land-based torpedo bombers northeast of Singapore. It was now clear that surface ships could not operate near enemy aircraft in daylight without air cover; most surface actions of 1942–43 were fought at night as a result. Generally, both sides avoided risking their battleships until the Japanese attack at Leyte Gulf in 1944.