Nine people have died and one is still missing in a fire that broke out on a fishing boat operating off this western port city, local maritime police said Saturday. 

The fire started at about 5:20 a.m. on the 20-ton fishing boat operating in the waters about 24 kilometers southwest of the port city, according to the police. Gunsan is located 274 kilometers south of Seoul.

The accident forced all 11 crew members on board to jump off the boat. Ten have been rescued but nine of them were pronounced dead later, with search efforts underway for the one missing crew member, the police said.

A witness said that he saw smoke coming out of the boat's engine room before the fire spread to the gas tanks. They put on life vests before jumping into the sea, he added.

"It seems that many of the people jumping into the sea died because of hypothermia caused by excessively low water temperature," a police officer said.

The police said that they are still investigating the exact cause of the fire and also trying to intensify those dead and missing. (Yonhap News)