Tokyo has called on Beijing to “guarantee the safety of Japanese expatriates in China” following a wave of phone harassment that targeted Japanese companies, sparked by the controversial release of cooling water from the Fukushima nuclear power plant.

China strongly opposed the discharge of water from Fukushima, filtered and diluted according to a method validated by the International Atomic Energy Agency (IAEA), and in particular suspended the import of Japanese seafood products.

Calls from China have been increasing since Thursday, when the operator Tepco, which manages the plant and the discharge at sea, began to discharge the water used to cool the damaged nuclear reactors of the Fukushima Daiichi nuclear power plant.

Hiroyuki Namazu, Japanese diplomat in charge of Asian and Oceanian affairs, asked senior officials at the Beijing embassy in Tokyo to call for calm, according to a statement from the Japanese foreign ministry released late Saturday. Similar things happened in China, Namazu told Chinese diplomats, according to the statement.

Appeal to discretion

“We urge the Chinese government to take appropriate measures, including calling on its citizens to act calmly, and to take all possible measures to ensure the safety of Japanese residents in China as well as Japanese diplomatic missions in China.” The Tokyo Embassy in Beijing has also invited its nationals to discretion.

A Fukushima businessman, quoted by the Kyodo news agency, said his four restaurants and patisseries received a thousand calls on Friday, most from China, leading staff to unplug the lines.

According to Fukushima Mayor Hiroshi Kohata, city departments received about 200 similar calls in two days. Schools, restaurants and hotels have also been victims of telephone harassment, he lamented. On social networks, Chinese Internet users have shared videos in which they show themselves calling Japanese numbers.

Japan plans to discharge more than 1.3 million cubic meters of water from Fukushima into the Pacific Ocean, in an extremely gradual way – until the early 2050s, according to the current schedule.

This water comes from rain, groundwater and the injections needed to cool the cores of the plant’s three reactors, which had gone into meltdown following the 2011 tsunami. It has been treated to rid it of its radioactive substances, to except for tritium, then diluted with seawater before discharge into the ocean so that the radioactivity does not exceed the limit of 1,500 becquerels per litre.

Japan’s environment ministry announced on Sunday that a new analysis of the water off Fukushima found no high levels of tritium and showed no signs of gamma radiation that could come from other radioactive materials.