Seoul: Two crew members from 14 rescued from a cargo ship that sank off southwestern Japan early on Wednesday have died, the coast guard said.

South Korean officials said nine of those rescued remain unconscious, but they did not immediately confirm any deaths. Ten crew members were later airlifted to Nagasaki in southern Japan for treatment, but two of them were confirmed dead on arrival, Japanese officials said.

South Korean and Japanese coast guard vessels and aircraft as well as two commercial cargo ships were continuing to search for the eight missing crew members but the efforts were being slowed by strong winds and waves, South Korean officials said.

The Japanese coast guard confirmed the rescue of at least 13 crew members and said five of them – all Chinese nationals – were still alive.

The 6551-tonne Jin Tian sank about 3.5 hours after it sent a distress call just before midnight on Tuesday in Japan’s exclusive economic zone, Japanese coast guard spokesperson Shinya Kitahara said.

The vessel, which was Hong Kong registered and carrying lumber, sank about 160 kilometres southwest of Nagasaki, Japan, and about 150 kilometres south of South Korea’s Jeju island.

The captain last communicated with the coast guard through a satellite phone around 2.41am, saying the crew would abandon the ship, minutes before it sank, Jeju Island coast guard officials said.

Six crew members were picked up by South Korean coast guard vessels, while a cargo ship picked up five and Japanese aircraft picked up three, according to Jeju’s coast guard.