The Tokyo Electric Power Co. (TEPCO) said Wednesday that it has stopped the leaking of radioactive water into the Pacific Ocean from Japan's crippled Fukushima nuclear plant, according to the company's website.

TEPCO said that it injected sodium silicate, a chemical agent known as "water glass", to seal a seaside pit from where large volumes of radioactive water had been leaking.

Radioactive iodine-131 was detected in the fish in a Japanese county on April 5, 2011.

Japan defended on Tuesday its dumping of thousands of tons of massive low-level radioactive water into the ocean. It said its action didn't violate international law and pledged to fully inform the international community of Tokyo's following steps to tackle the radiation emergency.

Kyodo news agency quoted Japanese Industry Minister Banri Kaieda as saying a total of 60,000 tons of radioactive water is believed to be flooding the basement of reactor buildings and underground trenches connected to them at the Fukushima nuclear plant, according to a China Daily report on Wednesday.

TEPCO said Tuesday that an estimated 3,430 tons of low radioactive water had been discharged into the Pacific Ocean.

TEPCO also said on Tuesday that it had found water with 5 million times the legal limit of radioactivity as it struggles for a fourth week to contain the world's biggest nuclear disaster in quarter of a century.