The operators of a stricken Japanese nuclear plant have apologised for a "mistake" in reporting a radiation spike 10 million times above normal.
Tokyo Electric Power Company, which has previously been criticised by officials for its handling of the crisis at the plant, said it got the readings wrong.
Despite the mistake, the radiation spike at reactor 2 was still very high and enough to evacuate workers.
The Fukushima Daiichi plant was damaged in the 11 March quake and tsunami.
The death toll from the quake and tsunami has now passed 10,000, and more than 17,000 people are missing.
The apology by the Tokyo Electric Power Company (Tepco) related to water readings at reactor 2 at the plant, 240km (150 miles) north of Tokyo.
It had said radiation levels reached 10 million times higher than normal in the cooling system but because the level was so high the worker taking the reading had to evacuate before confirming it with a second reading.
"The number is not credible. We are very sorry," said Tepco spokesman Takashi Kurita.
A spokesman for Japan's nuclear watchdog, Hidehiko Nishiyama, said the level of radiation in puddles near reactor 2 was confirmed at 1,000 millisieverts an hour.
"It is an extremely high figure," Mr Nishiyama said.
The radiation levels are so high, that emergency workers near the contaminated water would have received four times their maximum annual dose of radiation in just one hour.
The BBC's Mark Worthington in Tokyo says the erroneous report has created more confusion around a crisis that is already causing widespread unease in the country.
On Sunday, anti-nuclear protesters held a large rally in Tokyo, calling for change in Japan's nuclear industry.
Meanwhile, efforts are continuing to locate the exact source of the radioactive water leak, amid concerns that the water is leaking directly from the reactor itself.
Earlier, Japan's nuclear agency said that levels of radioactive iodine in the sea near the plant had risen to 1,850 times the usual level.
The emergency workers are also trying to cool the reactors in an effort to prevent a meltdown. They have now switched to using fresh water as a coolant, rather than sea water.
There had been fears the salt in sea water could further corrode machinery. The fresh water is being pumped in so that contaminated radioactive water can be extracted.
The UN's nuclear agency International Atomic Energy Agency (IAEA) has warned the crisis could go on for months.
However, the government in Tokyo has said that airborne radiation around the plant is decreasing, so there is no need to extend the evacuation zone.
Tepco has been criticised for a lack of transparency and failing to provide information more promptly and for making a number of mistakes, including worker clothing.