Up to 20 Chinese crewmembers are reported missing and one member dead after a cargo ship with 25 crew on board sank off Japan’s southern islands on 10 November.

The 17,000t Nasco Diamond went missing about 340km south of Iriomote Island in the Pacific.

The ship left Indonesia on 4 November carrying 55,000t of nickel ore for China.

So far, four crewmembers have been rescued and one dead body recovered, and search and rescue operations are underway to find other survivors.

The reason behind the wreck is not clear as weather conditions were favourable, although it is thought that Indonesian nickel ore is dangerous because it possesses high moisture content and increases the risks of the cargo liquefying.

One of the rescued crew informed Japanese officials that the vessel sank as soon as water entered into the engine room, according to lloydslist.com.