A Hong Kong-registered cargo ship carrying 22 crew members sank off South Korea's southern island of Jeju on Wednesday.
Five of the crew were rescued, while a search is under way for the others, the Coast Guard in South Korea said.
Fourteen Chinese and eight Myanmarese crew members were aboard the Jin Tian, a 6,551-ton, wood-carrying ship, when it sent out a distress signal in waters 148.2 kilometers southeast of the city of Seogwipo on Jeju Island, the Coast Guard said in a statement reported by Yonhap News Agency.
The ship was completely submerged when Coast Guard personnel arrived at the scene.
Five of the crew members were rescued by other ships that were sailing by, officials said, adding the Coast Guard is conducting a joint search and rescue operation with their Japanese counterparts for the 17 others.
The Coast Guard said the ship appears to have gone down when it sent the distress signal via the emergency position indicating radio beacon (EPIRB), an emergency locator system.