A South Korean soldier suspected of killing five of his comrades has exchanged fire with security forces seeking to capture him, media reports said.
The army sergeant opened fire at his pursuers near an elementary school in the Goseong region not far from the border with North Korea, Yonhap news agency and YTN television news reported on Sunday.
Al Jazeera's Harry Fawcett, reporting from Seoul, said authorities had identified the suspect as Sergeant Lim.
"There have been checkpoints stationed in many areas in case this man tries to get to populated areas," he said, adding that hundreds of families near the site of the standoff have been ordered to evacuate, to avoid being caught in the crossfire.
Our correspondent also said that between 3,000 to 4,000 troops have been deployed to hunt the suspect. The standoff continues as of Sunday afternoon.
The attack on Saturday at a military outpost in Gangwon province, northeast of Seoul, also wounded five other soldiers, the defence ministry said.
Local media earlier reported that the soldier fled with his weapon.
Thousands of troops from the rival Koreas are stationed along the world's most heavily armed border. There was no indication that North Korea was involved, but tensions between the rivals have been high recently, with North Korea staging a series of missile and artillery drills and threatening South Korea's leader.
In 2011, a 19-year-old marine corporal went on a shooting rampage at a Gwanghwa Island base, just south of the tense maritime border with North Korea.
Military investigators later said that corporal was angry about being shunned and slighted and showed signs of mental illness before the shooting.
In 2005, a soldier threw a hand grenade and opened fire at a front-line army unit in an attack that killed eight colleagues and injured several others. Pfc. Kim Dong-min told investigators he was enraged at superiors who verbally abused him.
All able-bodied South Korean men must serve about two years in the military under a conscription system aimed at countering aggression from North Korea.
The Korean Peninsula is still technically in a state of war as the 1950-53 Korean War ended with an armistice, not a peace treaty.
About 28,500 US soldiers are stationed in South Korea as a deterrent against North Korea.