Levels of radioactive iodine in the sea near the damaged Fukushima nuclear plant in Japan have risen further to 1,850 times higher than the usual level. Japan's nuclear agency said, it is believed the radiation is coming from one of the reactors, but a specific leak has not been identified. The plant's operator has been berated for a lack of transparency. The government said Tokyo Electric Power Co had to provide information more promptly. The nation's nuclear agency said the operator of the Fukushima plant had made a number of mistakes, including worker clothing.The death toll from the March 11 earthquake and tsunami has now passed 10,000, and more than 17,440 people are missing. Meanwhile, the UN nuclear watchdog, the International Atomic Energy Agency, has now sent extra teams to the Japanese nuclear plant. Officials say the radiation found in the sea will no longer be a risk after eight days because of iodine's half-life.