North Korea, a South Korean official said.The exact circumstances of the incident at the remote guard post were not immediately clear and the official could not provide further details, although there was no indication that North Korea was involved in the incident.
The incident took place in the Goseong county, a mountainous region that borders the North on the eastern end of the peninsula.
South Korea's Yonhap news agency said there was an operation to capture the conscript who is believed to be on the run carrying a firearm and live ammunitions.