TOKYO - The Tokyo Electric Power Company ( TEPCO) said Sunday that water contained radioactive materials probably leaked from a tank under the crippled Fukushima Daiichi nuclear plant, following the previous such incident reported Friday, according to local media.

TEPCO said the amount of contaminated water would be small as water level in the 60-meter-long, 53-meter-wide and 6-meter-deep container has not lowered significantly, Kyodo News Agency reported.

About 120 tons of contaminated water allegedly leaked into soil from another tank on Friday, Kyodo said Saturday.

A total of seven tanks with similar design and covered by three layers of waterproof sheets contained water to cool nuclear reactors in the complex, which was damaged in the catastrophic tsunami in March 2011.

The TEPCO said around 6,000 becquerels of radiation per cubic centimeter were logged on Friday in water between the sheets and trace amount of radioactive substances were also detected in water between the outermost sheet and the soil, Kyodo said.

The containers are around 800 meters from sea and the company said it believes the polluted water is unlikely to flow into the sea, said the report.