Fukushima Daiichi Reactor
The damaged roof of reactor number No. 1 at the Fukushima Daiichi nuclear plant after an explosion that blew off the upper part of the structure is seen in this handout photo released by Tokyo Electric Power Company (TEPCO) in Fukushima Prefecture, northeastern Japan, March 12. Japanese authorities battling to contain rising pressure in nuclear reactors damaged by a massive earthquake were forced to release radioactive steam from one plant on March 12 after evacuating tens of thousands of residents from the area. Tokyo Electric Power Co. also said fuel may have been damaged by falling water levels at the Daiichi facility, one of its two nuclear power plants in Fukushima, some 240 km (150 miles) north of Tokyo. REUTERS

Japan has informed the International Atomic Energy Agency (IAEA) that a spent fuel storage pond at an earthquake-hit reactor is on fire and radioactivity is being released directly into the atmosphere, the Vienna-based U.N. atomic watchdog said.

Japan told the IAEA that dose rates of up to 400 millisievert per hour have been reported at the Fukushima Daiichi nuclear power plant site. The Japanese authorities are saying that there is a possibility that the fire was caused by a hydrogen explosion, IAEA said.

The IAEA said it is seeking further information on these developments, adding it continues to liaise with the Japanese authorities and is monitoring the situation as it evolves.

The powerful earthquake, the largest earthquake recorded in the country, struck Japan on Friday which was followed by a devastating tsunami and subsequent threats of a nuclear outbreak and volcanic activity.