Japan has declared states of emergency at two nuclear plants damaged by Friday's massive earthquake along the country's northeastern coast.
The country's Tepco electric company says an explosion occurred Saturday at one of the plants, injuring four people. Few other details were immediately available.
Authorities earlier said radioactive material had been found outside one of the plant's reactors, which had lost power and cooling abilities following the magnitude 8.9 quake and tsunami.
Authorities said they were trying to determine if a meltdown occurred. They said such a development would not pose a danger to people outside the already established 10 kilometer evacuation zone.
Prime Minister Naoto Kan flew over Fukushima in a helicopter on Saturday to assess the damage and said 50,000 troops would join rescue and recovery efforts.
Japanese media report more than 1,200 people are dead or missing.
Entire villages were washed away Friday by waves as high as 10 meters that carried vehicles, buildings and debris several kilometers inland. The earthquake and tsunami damaged highways and other infrastructure, further hampering rescuers' efforts to reach people stranded on their roofs and trapped in affected areas.
Japan's Tepco electric company is warning of massive power outages in the coming days across large areas of the country.
Japanese authorities said 200 to 300 bodies have been found in Sendai, the city closest to the quake, which was the most powerful on record to hit Japan and the world's fifth largest in more than a century. They say 700 people are missing and 1,000 people have been injured.
Northeast of Sendai, fires raged through the night Friday in Kesennuma, a town of 70,000 people. A large fire also erupted at an oil refinery in Ichihara, near Tokyo.
In Tokyo, the quake forced a suspension of all train and subway services, leaving millions of people stranded. Several airports were also closed, but some, including Tokyo's Narita have reopened.
Officials said the 8.9 magnitude quake and subsequent tsunami knocked power out and caused cooling systems to fail at two plants in Fukushima.
Radioactive material has been found outside one reactor, where officials say they are trying to determine if a meltdown has occurred. Authorities said the development would not pose a danger to people outside the already established 10 kilometer evacuation zone.
Prime Minister Naoto Kan flew over Fukushima in a helicopter on Saturday to assess the damage and said 50,000 troops would join rescue and recovery efforts.
Japanese media report more than 1200 people are dead or missing.
Entire villages were washed away Friday by waves as high as 10 meters that carried vehicles, buildings and debris several kilometers inland. The earthquake and tsunami damaged highways and other infrastructure, further hampering rescuers' efforts to reach people stranded on their roofs and trapped in affected areas.
Japan's Tepco electric company is warning of massive power outages in the coming days across large areas of the country.
Japanese authorities said 200 to 300 bodies have been found in Sendai, the city closest to the quake, which was the most powerful on record to hit Japan and the world's fifth largest in more than a century. They say 700 people are missing and 1,000 people have been injured.
Northeast of Sendai, fires raged through the night Friday in Kesennuma, a town of 70,000 people. A large fire also erupted at an oil refinery in Ichihara, near Tokyo.
In Tokyo, the quake forced a suspension of all train and subway services, leaving millions of people stranded. Several airports were also closed, but some, including Tokyo's Narita have reopened.