OSAKA -- Two explosions ripped through a first floor restroom in Osaka City Hall Monday afternoon, forcing the evacuation of some 3,000 employees for about an hour.
No injuries were reported from the blasts, which occurred just before 4 p.m. in the men's toilet. Police investigators discovered several gas canisters and paint thinner bottles in the men's room after the blasts.
According to Toshio Nakatsuji, an Osaka municipal official, white smoke was seen pouring out of the bathroom, which is located near the citizens information center, by a city employee at about 3:50 p.m.
"Less than a minute after the smoke was discovered, two explosions were heard and the order to evacuate the building was given," Nakatsuji said.
Nobody was in the men's room at the time of the explosion, Nakatsuji said. One woman who was in the adjacent ladies room escaped unharmed. The ceiling sprinkler system immediately extinguished the fire, police said.
Mayor Takafumi Isomura, who was on a different floor and evacuated without incident, was not immediately available for comment on the blast.
Osaka officials say the explosions occurred with no prior warning, and the mayor's office said they had not received any threatening phone calls.
Police were continuing their investigation but as of early evening had no suspects. The city hall is in the Nakanoshima business area of Osaka's Kita Ward, and 1.2 km southeast of JR Osaka Station.