First details of American losses in the Japanese attack on Pearl Harbour, Hawaii, on Dec. 7, were given by Col. Knox, U.S. Navy Secretary, on his return on Dec. 15 from a visit of investigation. The battleship Arizona was sunk through "a lucky hit"; three destroyers, the Cassin, Downes and Shaw, each of 1,500 tons, were also sunk, together with a minelayer, the Oglala, and an old wireless-controlled target ship, Utah. The battleship Oklahoma capsized, but Col. Knox stated that she could be righted and repaired. Casualties among personnel amounted to 2,729 naval officers and men killed and 656 wounded, while Army casualties totalled 168 killed, 223 wounded and 26 missing. Losses in aircraft were severe.
"The U.S. surface ships were not on the alert against a surprise air attack", said Col. Knox, "but the Japanese failed in their purpose – to knock out the United States before the war began".