Radioactive water have escaped from the crippled Fukushima nuclear plant in Japan and some may have leaked into the Pacific Ocean.
The plant's operator said about 45 tonnes of water was found outside a purification device on Sunday morning.
The Tokyo Electric Power Company says about 300 litres leaked through a crack in a wall and may have reached the sea.
TEPCO said the water contained caesium at levels roughly the same as or slightly higher than seawater near the plant.
The nuclear plant was crippled by the earthquake and tsunami on 11 March. A 20km exclusion zone remains in place.