"The site is effectively out of control," energy commissioner Guenther Oettinger told a European Parliament committee, one day after he said Japan was facing "apocalypse."

"In the coming hours there could be further catastrophic events which could pose a threat to the lives of people on the island," he said.

Scrambling to prevent a nuclear meltdown, Japanese crews have been dumping water on the stricken Fukushima No.1 power plant, which has been hit by a series of explosions after Friday's quake knocked out reactor cooling systems.