Komeito, the junior coalition partner of Japan's ruling Liberal Democratic Party, said Saturday its chief will postpone a trip to China amid strong protest from Beijing over the release of treated radioactive water from the crippled Fukushima nuclear plant into the sea.

Natsuo Yamaguchi had planned to visit China from Monday through Wednesday. But Komeito has been told by the Chinese side that "it is not the right time in view of the current situation of Japan-China relations," the party said.

Yamaguchi separately told Kyodo News that he regrets the postponement. "I don't think the release of treated water...did not affect" the planned visit.

Prime Minister Fumio Kishida had asked Yamaguchi to pass on a letter from him to Chinese President Xi Jinping.

Japan started releasing the water Thursday from the Fukushima Daiichi complex, wrecked by the 2011 earthquake and tsunami.

Local fishermen have also voiced concerns about the environmental impact, although the U.N. nuclear watchdog has said the procedure aligned with global safety standards.

On Thursday, China banned imports of all seafood products from Japan following the start of water release.

Related coverage:

China bans operators from processing seafood originating in Japan

Tritium not detected in samples from waters off Fukushima plant

No anomalies detected in fish samples after Fukushima water release