Military prosecutors sought capital punishment for an Army sergeant on Tuesday for killing and wounding a dozen unarmed fellow soldiers in a shooting rampage at a military outpost near the tensely-guarded eastern border with North Korea last year.

The 23-year-old conscript, surnamed Lim, detonated a grenade and sprayed a hail of bullets in June last year in the military outpost of the 22nd Infantry Division stationed near the east-coastal front line, killing five comrades and wounding seven others. 

Lim was sentenced to death by a local military court in February before appealing to the military appellate court. 

The killing of five fellow soldiers and the military vacuum at the front line that the shooting rampage caused were cited as major reasons when prosecutors again sought the death penalty for Lim.

"Sergeant Lim only blamed his comrades without proper self-examination," a military prosecutor said, dismissing Lim's defense that the shooting was a result of extreme distress stemming from bullying he faced inside the barracks.

"I am still feeling deeply guilty and responsible ... I am sincerely sorry," Lim said as he tearfully read out his final testimony.

Following the shooting rampage, Kim ran away with a rifle and attempted to shoot himself to death before being captured alive two days later. (Yonhap)