INCHEON (Yonhap News) -- A freight ship carrying oil exploded in waters off the port city of Incheon Sunday morning, killing three crew members and causing eight others to go missing, the Coast Guard said.

The 4191-ton vessel's explosion took place in waters three miles north of Jawol Island near Incheon around at 8:05 a.m., the Coast Guard said. Five people aboard the ship were rescued, it said.

A total of 11 Korean and five Myanmarese crewmen were aboard the ship, the Coast Guard said. The exact cause of the explosion was not immediately known.