A hand grenade held by a recently enlisted soldier exploded at a guard post near the border with North Korea on Saturday, instantly killing the soldier and seriously wounding his platoon leader, military and police officials said Saturday.
   
The explosion occurred at around 5:05 a.m. when the 21-year-old private, identified by his surname Choe, and his platoon leader were inside the post just south of the western section of the Demilitarized Zone, according to officials.
   
Choe died at the scene, and the platoon leader, identified as 2nd Lt. Park, 24, sustained serious wounds to his head, neck and other parts of his body. Park received surgery at a hospital in Suwon, south of Seoul, to remove shrapnel. The wounds are not life-threatening, officials said.
  
The cause of the explosion is under investigation.
   
Officials said they are looking into various possibilities, including whether Choe, who had been posted at the unit just five days earlier after completing basic training, attempted suicide or if he had mishandled the grenade.
   
Park was quoted as telling officials before being taken to the hospital that he was dozing off inside the guard post at the time of the explosion, and dashed out of there after hearing the blast. (Yonhap News)