China on Friday banned food production operators from purchasing or using seafood originating in Japan to process it for sale, a day after suspending all marine product imports from the neighboring country.

The fresh measure was announced in response to Japan's release of treated radioactive water from the crippled Fukushima nuclear plant into the sea that started Thursday. China vehemently opposes the ocean discharge.

Photo taken in Beijing on Aug. 25, 2023, shows Chinese newspaper reports on Japan beginning its discharge of treated radioactive water from the crippled Fukushima Daiichi nuclear power plant into the sea. (Kyodo)

The State Administration for Market Regulation also said it will strengthen the monitoring of imported aquatic products to ensure food safety.

The Fukushima plant's operator, Tokyo Electric Power Company Holdings Inc., said Friday the level of tritium, a radioactive substance that is said to pose little risk to human health and the environment, was undetectable in samples taken shortly after the discharge began the previous day.

When asked about the monitoring result at a press conference Friday, Chinese Foreign Ministry spokesman Wang Wenbin did not comment on it, just repeating Beijing's claim that the Fukushima water release is an "extremely irresponsible and selfish" act and Japan is "shifting the risk of nuclear pollution to other countries."

Wang said China and other countries have the right to take legitimate measures to "ensure a sound marine environment and the health and the well-being" of people.

Since the 2011 nuclear disaster, water at the Fukushima plant has been treated using an advanced liquid processing system capable of removing most radionuclides except tritium after cooling melted nuclear fuel.

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