TOKYO (Reuters) - Tokyo Electric Power Co. shut down three major generators at the world's biggest nuclear power plant after a powerful earthquake in Japan on Monday caused a brief fire in one of the units, company officials said.

TEPCO, Asia's biggest utility, added that 1.5 liters of water containing radioactive materials had leaked from a unit closed for maintenance at the Kashiwazaki-Kariwa nuclear power plant.

The contaminated water was released into the ocean and had had no effect on the environment, TEPCO said in a statement. The company had previously said there had been no radiation leaks at the plant, where reactors automatically shut down for checks.