Personnel from Japan's Self-Defense Forces in protective gear take part in a nuclear, biological and chemical weapons (NBC) exercise, held as a part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. Japan, Australia, South Korea and Singapore are taking part in the three-day drill to improve their capability to prevent possible transport of weapons of mass destruction by air. [Photo/Agencies]

Japanese police officers in protective gear take part in a nuclear, biological and chemical weapons (NBC) exercise, held as a part of a drill for the Proliferation Security Initiative (PSI) Air Interdiction Exercise "Pacific Shield 12", at New Chitose airport in Chitose on Japan's northern island of Hokkaido July 4, 2012. [Photo/Agencies]