With most of Australia's best forces committed to fight against Hitler in the Middle East, Japan attacked Pearl Harbor, the US naval base in Hawaii, on 8 December 1941 (eastern Australia time). The British battleship and battlecruiser sent to defend Singapore were sunk soon afterwards. Australia was ill-prepared for an attack, lacking armaments, modern fighter aircraft, heavy bombers, and aircraft carriers. While demanding reinforcements from Churchill, on 27 December 1941 Curtin published an historic announcement: