Beijing lashed out at Tokyo on Thursday after it began dumping water from Japan’s damaged Fukushima Daiichi nuclear power plant into the Pacific Ocean, denouncing a “selfish and irresponsible” action. China suspended fish imports from Japan.

A few minutes earlier, the Japanese authorities had activated pumps and valves to channel the waters into the sea.

This first drop is expected to last around 17 days and involves approx 7,800 cubic meters of water of the nuclear power plant which contains tritium, a radioactive substance that is only dangerous in highly concentrated doses.

“China is categorically opposed and strongly condemns (this decision). It has formally protested to Japan, demanding that it put an end to this reprehensible action,” a spokesperson for the Chinese Foreign Ministry responded in a statement.

“The ocean is humanity’s common good. Discharge of contaminated water into the sea emanating from the Fukushima nuclear power plant is a highly selfish and irresponsible action that has no regard for the international public interest.”

In total, Japan must dump into the Pacific Ocean more than 1.3 million cubic meters of water previously stored at the nuclear plant site.

They come from rainwater, groundwater and added water that was necessary to cool reactor cores that had begun to melt after the March 2011 tsunami that hit the country’s northeast coast.

“The Japanese government has not proven that these discharges are legitimate” or that they are harmless to the marine environment and human health, the Chinese Foreign Ministry claims.

“What Japan is doing is to conveys to the whole world the dangers (associated with these waters) and prolong the pain (associated with the disaster) to future generations,” he said.

However, the International Atomic Energy Agency (IAEA), which oversees the water disposal operation, gave the go-ahead for her in July, considering that the plan is in line “with international safety standards” and that the radiological impact will be “negligible for the population and the environment”.