Rescue teams off the south-eastern coast of the United States are searching on Monday for four crew members from a cargo ship which overturned on Saturday.
Twenty people on board the Golden Ray were rescued after the vessel tilted over on its side on Saturday night near the port of Brunswick in the state of Georgia.
According to the Foreign Ministry in Seoul the missing crew members were South Korean.
They are thought likely to be in the machine room of the stricken freighter, which was transporting cars.
The cause of the accident is not yet clear.
The boat is owned by South Korean logistics firm Hyundai Glovis and was built in 2017.