Tokyo, July 3: An explosion at a building in Tokyo's commercial district of Shimbashi on Monday shattered windows and spewed smoke, according to media reports. Japan Fire: Blaze Erupts at Kashiwazaki-Kariwa Nuclear Power Plant in Niigata.

Police were investigating the site after receiving an emergency call, Kyodo news reported. Shooting in Japan: Two Soldiers Killed After Japanese Cadet Opens Fire at Colleagues at Firing Range in Gifu, Attacker Arrested.

NHK television, quoting fire department officials, said four people were injured. No other information, including the cause, was yet available.