Extremely high levels of radiation have been detected in water leaking from reactor two of Japan's stricken Fukushima nuclear plant, forcing the evacuation of workers.
The operator, Tokyo Electric Power Co, said the level of radiation found in the leaked water was 10 million times higher than it should be for water inside the reactor, indicating damage to the fuel rods.
It says it detected 1000 millisieverts per hour of radiation in a puddle of water at the reactor number two.
The company says high levels of caesium and other substances are being detected, which usually should not be found in reactor water.
It says there is a high possibility that fuel rods are being damaged.
Levels rise in sea water
Earlier Japan's nuclear safety agency said levels of radioactive iodine in the sea near the damaged Fukushima nuclear plant had risen to 1850 times the normal level.
It is believed the radiation is coming from one of the reactors, but a specific leak has not been identified reports the BBC.
Meanwhile, the agency says leakage from reactor vessels at the plant is likely to have been the cause for high levels of radiation found in water that has accumulated in turbine buildings.
Japanese engineers are struggling to pump the radioactive water from the nuclear power station and the situation has hampered workers from restoring the plant's cooling systems.
Lack of transparency criticised
The operator of the nuclear plant has been criticised by government officials for a lack of transparency and failure to protect its workers.
The government said Tokyo Electric Power Co has to provide information more promptly.
In addition, the Nuclear & Industrial Safety Agency said the operator of the Fukushima plant had made a number of mistakes, including inadequate worker clothing.
Three workers were this week exposed to radiation levels 10,000 times higher than normal, suffering burns.
The plant was damaged in the earthquake and tsunami on 11 March.
The death toll has now passed 10,000 and more than 17,440 people are missing.
NISA said TEPCO knew of high air radiation at one reactor several days before the exposure incident at the Fukushima Daiichi plant 240km north of Tokyo.
Radioactive water has been found in three of the six reactors reports the BBC.
Four of the reactors are still considered volatile.
Tests on Friday showed that levels of iodine 131 in seawater 30km from the complex had spiked 1250 times higher than normal.
However, NISA said this was not considered a threat to marine life or food safety.
The International Atomic Energy Agency has now sent extra teams to the Fukushima plant.
IAEA director Yukiya Amano told the New York Times that the emergency could last weeks, if not months.