A North Korean man crossed the heavily fortified Demilitarized Zone into South Korea on Thursday and was detained by Seoul’s military after a 20-hour operation.

He was found near the Military Demarcation Line and safely guided out of the DMZ. Such land-border defections are rare due to heavy fortifications and landmines.

South Korean authorities will investigate the incident.

No unusual North Korean military activity was detected, CBS News has reported.

The defection comes as South Korea’s new president, Lee Jae Myung, calls for more dialogue with Pyongyang.

Written by B.C. Begley