TOKYO: Approximately 5.5 tons of water containing radioactive materials have leaked from equipment at Japan's Fukushima Daiichi nuclear power plant, local media reported.

Workers discovered water leaking from the outlet of a device used to purify nuclear-contaminated water, Fukushima Central Television reported, citing the plant's operator Tokyo Electric Power Company (TEPCO).

TEPCO estimates that the amount of water that leaked was approximately 5.5 tons, which may contain 22 billion becquerels of radioactive materials such as cesium and strontium, Xinhua news agency reported quoting local media.