North Korea has detained a U.S. citizen who illegally crossed the border while taking part in a tour of the Truce Village in the demilitarized zone separating the two Koreas.

Private Travis King was stationed in South Korea but was recently taken into custody after an altercation with locals. On Monday, he was escorted to Incheon International Airport to face disciplinary action in the U.S., but those escorting him were not allowed to go beyond the customs checkpoint.

After entering the airport's secure area, he failed to go to his gate and instead joined a tour group heading to the demilitarized zone. While there, he reportedly was hearing saying "ha ha ha" before running across the border. He was then taken into custody by North Korean soldiers.