The Japanese embassy in Beijing is urging Chinese authorities to take strict action in accordance with the law with abusive phone calls being made from China to individuals and organizations in Japan.

China strongly opposes Japan's release of treated and diluted water from the crippled Fukushima Daiichi nuclear power plant into the ocean and suspended all imports of seafood from Japan on Thursday.

The Japanese embassy says phone calls from China are being made to individuals and organizations in Japan that are not related to the treated water release.

Japanese people living in China are also being targeted.

A Japanese restaurant in Guangzhou in southern China says a Chinese visitor threatened to report the establishment to the authorities if it was using Japanese-made ingredients.

Another restaurant was reportedly investigated by the authorities, without prior notice, to see if it was using Japanese seafood.

Japanese companies and department stores were attacked after the Japanese government purchased the Senkaku Islands in Okinawa Prefecture from a private Japanese owner in 2012.

Japan controls the islands. The Japanese government maintains the islands are an inherent part of Japan's territory. China and Taiwan claim them.

The embassy is calling on Japanese nationals living in China not to speak unnecessarily loudly in Japanese when they go out.