Seventeen Vietnamese crew members of a Panamanian-registered cargo ship were rescued, while one remains missing, after the ship sent a distress signal off the coast of Shimane Prefecture, the coast guard said Thursday.

The missing crew member of the Houei Crystal fell into the sea from the deck of the 5,762-ton vessel at around 8:30 a.m. on Wednesday, hours before it sent the distress signal at around 4:30 p.m. the same day, according to Japan's 8th Regional Coast Guard Headquarters.

The ship, which was transporting about 8,000 tons of coal from Russia's Nakhodka to Kinuura, Aichi Prefecture, sent the signal from waters 380 kilometers northwest of the Oki Islands and later sank.

The 17 crew members escaped using a lifeboat and were rescued by South Korean authorities about 12 hours later.

None of them are in a life-threatening condition, the coast guard said.