Explosion in central Tokyo triggered by methane gas

An explosion at a women's spa in central Tokyo killed three people and injured at least three others.

The afternoon explosion appeared to have been triggered by methane gas that seeped from the ground beneath the popular "Shiespa" hot spring and caught fire, according to police.

Authorities had earlier said a boiler at the spa had exploded. The main building apparently did not sustain major damage, but was being examined.

Police and fire officials said three people had been confirmed hurt in the explosion. Police said one of the three killed was a woman, but could not confirm the gender of the other fatalities.

News reports said three other people had been injured, including passers-by.

After dousing the flames, fire officials swarmed the blasted shell of the building, which was destroyed except for the mangled iron frame.

Debris had been blown in to the street and against the neighboring apartment houses, shattering windows.

"I heard a huge boom. When I jumped outside, I saw a plume of smoke," said Miki Yamagishi, a clerk at a nearby convenience store.

Shiespa is a women's only spa with a natural hot spring, an open-air bath, a sauna and salon, according to its Web site.