A South Korean coast guard boat capsized Thursday while carrying out a rescue mission, resulting in the deaths of three sailors, officials said. The boat was transporting 15 sailors from a troubled Malaysian cargo ship off the west coast of Jeju Island when high waves turned it over, Yonhap News Agency reported. The three sailors from the Malaysian ship were taken to a nearby hospital but pronounced dead on arrival. Two other sailors were injured and were unconscious when they arrived at the hospital. The Malaysian vessel was heading to Singapore when it began taking on water and requested help from the coast guard.