At least nine people were killed when a South Korean-flagged vessel capsized off Japan, South Korea's foreign ministry said on Thursday.

Two South Korean nationals were among the dead, it said, adding that the Japanese coastguard had rescued an Indonesian crew member and that another member of the crew of 11 was missing.

Japanese public broadcaster NHK reported on Wednesday that a South Korean-flagged chemical tanker had capsized off the coast of Yamaguchi prefecture in western Japan.