TOKYO - (AP) - Emergency workers struggling to pump contaminatedwater from Japan's stricken nuclear complex fled from one of thetroubled reactors Sunday after reporting a huge increase inradioactivity - a spike that officials later apologetically saidwas inaccurate.

The apology came after employees fled the complex's Unit 2reactor when a reading showed radiation levels had reached 10million times higher than normal in the reactor's cooling system.Officials said they were so high that the worker taking themeasurements had withdrawn before taking a second reading.

On Sunday night, though, plant operators said that while thewater was contaminated with radiation, the extremely high readingwas a mistake.

"The number is not credible," said Tokyo Electric Power Co.spokesman Takashi Kurita. "We are very sorry."

He said officials were taking another sample to get accuratelevels, but did not know when the results would be announced.

The situation came as officials acknowledged there wasradioactive water in all four of the Fukushima Dai-ichi complex'smost troubled reactors, and as airborne radiation in Unit 2measured 1,000 millisieverts per hour - four times the limit deemedsafe by the government, Kurita said.

Officials say they still don't know where the radioactive wateris coming from, though government spokesman Yukio Edano has saidsome is "almost certainly" seeping from a cracked reactor core inone of the units.

While the discovery of the high radiation levels - and theevacuation of workers from one reactor unit - again delayed effortsto bring the deeply troubled complex under control, Edano insistedthe situation had partially stabilized.

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Concern in Tokyo over radiation in tap waterPower lines up in progress at Japan nuclear plantJapanese helicopters drop seawater on nuclear reactor