Japan quake: evacuations near nuclear plants

A Japanese nuclear power plant was hit by an explosion, raising fears of a radioactive meltdown, a day after a massive quake damaged the facility's cooling system.

The top government spokesman said tens of thousands of people within 10 kilometres (six miles) of the plant should evacuate, calling for a "calm response", and saying radiation was "at assumed levels".

Kyodo News said the hourly radiation matched the allowable annual dose.

TV channels warned nearby residents to stay indoors, turn off air-conditioners and not to drink tap water.

People going outside were also told to avoid exposing their skin and to cover their faces with masks and wet towels.

Nuclear authorities had earlier warned that the Fukushima No. 1 plant, located about 250 kilometres (160 miles) northeast of Tokyo, an urban area of 30 million people, "may be experiencing a nuclear meltdown".

The plant's cooling system was damaged in the quake that hit Friday, leaving the government scrambling to fix the problem and evacuate more than 45,000 residents within a 10-kilometre (six-mile) radius.

Public broadcaster NHK reported that a blast had been heard at about 3:30 pm (0630 GMT) and showed delayed footage of smoke billowing from the site, then reported that the reactor building had been destroyed.

Operator Tokyo Electric Power confirmed the explosion and that the roof of the reactor building had collapsed, saying this had happened during an aftershock to Friday's quake, Kyodo News reported.

Tepco also confirmed that four of its workers had been injured, saying that the injuries were not life-threatening.

Prime Minister Naoto Kan's right-hand man, Chief Cabinet Secretary Yukio Edano, told a press conference that the Tokyo Fire Department would send a "hyper rescue team" to the site.

He also said the government was taking contingency measures and collecting iodine, with can be used against radiation sickness.