Around 1 million nuisance calls have been made to the Japanese Embassy in Beijing since the release into the sea of treated radioactive water from the crippled Fukushima nuclear power plant began in late August, Japanese government sources said Friday.

Tokyo has repeatedly asked the Chinese government to deal with the calls, saying they impede operations at the embassy, but the situation has yet to improve, according to the sources.

On the back of growing anti-Japan sentiment in China amid Beijing's fierce opposition to the discharge, the daily number of harassing calls received by the embassy peaked at more than 40,000 on Aug. 25, a day after the release started, and has stayed at around 15,000 per day recently, they said.

In most cases, callers harshly criticize Japan over the water release or remain silent. The calls have also included bomb threats, the sources said.

Japanese Ambassador to China, Hideo Tarumi, addressed the harassing calls and emphasized the necessity of "recovering our senses" to enhance bilateral relations in his speech at a forum held in Beijing last week.

Chinese Foreign Ministry spokeswoman Mao Ning said at a news conference Friday that China has "always protected the safety of embassies" in accordance with the law, as well as "the legitimate rights and interests of foreign citizens in China."

In response to the water discharge, China imposed a blanket import ban on Japanese fishery products.