Five soldiers were killed and seven others wounded on Saturday evening after a sergeant went on a shooting rampage in his unit near the eastern inter-Korean border, the Defense Ministry said Sunday.

The 22-year-old sergeant, who is identified only by his surname Lim, is currently at large. The military is now in a frantic search for him in the vicinity of his unit in Goseong, Gangwon Province, as he now carries a K-2 rifle with some 60 bullets.

During his shooting spree, Lim detonated one grenade at around 8:15 p.m. and fired some 10 shots in and outside his barracks after vigilance duty at a general outpost.

Two of the five wounded soldiers were immediately transported by helicopter to a military hospital in Seongnam, Gyeonggi Province. The two received emergency surgery and are now in stable condition. The rest suffered minor injuries and are being treated at a hospital in Gangneung, Gangwon Province, officials said.

“After detonating a grenade, he (Lim) fired shots toward the barracks, killing three soldiers, and then he entered the hall of the barracks, killing two inside the barracks,” ministry spokesperson Kim Min-seok told reporters.

“We are deeply sorry to the people for causing concerns. We pray for the sacrificed soldiers and extend our condolences to the bereaved families, and will do our best to support them.”

The ministry set up an investigative team consisting of 48 military officers to find out about the motives behind his shooting. The team is currently gathering statements from Lim’s colleagues and bereaved families.

During the initial personality test in April 2013, Lim was classified as an “A-grade” soldier who needed “special attention.” Seven months later, he was classified as a “B-grade” soldier who needed attention, but was able to carry out vigilance duty with sufficient guidance.

Lim joined the Army in December 2012 and was to be discharged in September.

The incident is the worst case since June 2005 when a soldier went on a shooting rampage and detonated a grenade, leaving eight people dead and two seriously wounded.

By Song Sang-ho (sshluck@heraldcorp.com)