A South Korea-flagged chemical tanker capsized in waters off the Japanese city of Shimonoseki in Yamaguchi Prefecture in the west of Honshu Island.

According to Japan's public broadcaster NHK, citing the Japan Coast Guard, a request for search and rescue was received at around 7 a.m. Wednesday from the South Korea-registered KEOYOUNG SUN vessel, which was reported to be listing to one side.

While eleven people — two South Koreans, eight Indonesians and one Chinese national — had been onboard at the time, four have so far been rescued.

The Japanese Coast Guard is continuing its search and rescue operation using aircraft and patrol boats.

The transport vessel had reportedly been anchored due to bad weather conditions, with waves in nearby waters reaching a height of three-point-five meters.