A North Korean has been caught and is in South Korea's custody after crossing the inter-Korean border at the heavily-fortified Demilitarized Zone, according to the Yonhap news agency. The incident happened around 11:38 p.m. Wednesday, according to South Korea's Joint Chiefs of Staff.

There was no immediate word as to the man's identity or reason behind his defection. He was moving south near the Imjin River when South Korea troops apprehended him, according to the Reuters news agency.

"An investigation is underway to determine the details, including whether he was to defect to South Korea and the course of his border crossing," JCS said in a statement.

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The DMZ is known to be surrounded by landmines, fences, guard posts and other military equipment on both sides of the border, Reuters reports.

According to Reuters, hundreds of North Koreans make a journey to South Korea each year hoping to defect, but unauthorized DMZ crossings are rare. In 2017, a North Korean soldier attempted to defect but was shot by fellow soldiers as he fled across the border into South Korea where he received medical treatment.