A South Korean soldier is on the run after shooting five comrades dead and injuring another five at the border with North Korea, according to South Korean media reports.
South Korea's Yonhap news agency reported that a South Korean army private fled after opening fire on his comrades at an outpost in Gangwon province, east of Seoul.
South Korean military officials were not available for comment.
Thousands of soldiers from the rival Koreas square off along the world's most heavily armed border.
There is no indication that North Korea was involved, but tensions have been high recently, with North Korea staging a series of missile and artillery drills and threatening South Korea's leader.