Commemorations to mark the 70th anniversary of the Japanese attack on the US Pacific Fleet at Pearl Harbour are being held across the United States.
The main remembrance ceremony were held at Pearl Harbour in Honolulu.
More than 2000 servicemen and civilians were killed and 18 American warships were sunk or damaged in the attack on 7 December, 1941.
Denouncing "a date which will live in infamy", President Franklin Roosevelt went to Congress for a declaration of war, which was approved within hours.
Three days later, Germany declared war on the United States. America's entry was to change the course of the conflict.
A ceremony was held by the wreck of the USS Arizona at 7.55am on Wednesday, marking the moment when Japanese bombers swooped on the US Pacific Fleet at Pearl Harbor.
The USS Arizona was one of 12 vessels sunk that day. Nearly half died almost instantly when a bomb detonated the battleship's munitions store.
Defence Secretary Leon Panetta laid a wreath at the US Navy Memorial in Washington DC at midday.