SEOUL - South Korean special forces joined a manhunt on Sunday for a soldier who killed five comrades in a grenade and gun attack at a base near the North Korean border, and once dawn broke military helicopters began scouring the forested hillsides.
The soldier shot dead five of his fellow unit members and wounded seven others late on Saturday at a outpost in the base at Goseong county, a mountainous region that borders the North on the eastern coast of the peninsula.
He then fled into the night carrying a firearm, ammunition and a grenade, according to military officials.
Yonhap news agency named the soldier, and gave more details of what happened at the base. "Sergeant Lim was to be discharged three months later on September 16," Yonhap reported. "He first threw a grenade and then opened fire. He was returning after completing his day shift duty."
The number of military personnel involved in the search was the equivalent of nine battalions, a colonel with the Army's Eighth Corps told a media briefing.
Yonhap reported that special forces had been deployed and helicopters were sweeping the search area. "A cordon operation is underway along with guard posts in the demilitarized zone," a military official was quoted as saying.
The Demilitarized Zone is a 4-kilometre (2.5-mile) wide swathe of land serving as a buffer between the two Koreas since the end of the 1950-53 Korean War. "We have secured a cordon that will prevent him from entering areas where civilians live. We have notified village foremen to make sure residents do not move around and report to us if they spot the shooter," the official said.
The shooting comes at a sensitive period for South Korea, with the nation still in shock after the death of more than 300 people, mostly school children, in a ferry disaster in April.
The defense ministry issued an apology to the nation over the shooting. The military has been criticised over similar incidents in the past.
"I offer my sincere apology to Koreans for causing worry,"said Kim Min-seok, the ministry spokesman.
"We have formed a team of 48 to investigate the accident and will have families of the dead present at the crime scene investigation."
The military has been criticized before for lax discipline in some units and failure to prevent previous cases where soldiers, suffering personal problems, have shot fellow soldiers.
All able-bodied South Korean men must serve about two years under a conscription system, and there are concerns that new recruits are softer than in the past, and find it harder to adapt to military life.
The South Korean military has more than 600,000 troops, aimed at deterring aggression by North Korea, which is one of the world's most militarised states. North and South Korea are technically still at war after their 1950-53 conflict ended in a truce, not a peace treaty.
In a similar incident in 2011, a South Korean marine went on a shooting spree at a base near the tense maritime border with North Korea, killing four fellow soldiers before trying to blow himself up with a hand grenade.