Authorities say a North Korean civilian crossed the heavily fortified border into South Korea on Thursday. 

South Korea’s Joint Chiefs of Staff(JCS) said Friday that it took the individual into custody near the military demarcation line Thursday night. 

The JCS said the South Korean military detected and tracked the North Korean in the area and took the person into custody through a standard operation, adding that the authorities will investigate the circumstances of the crossing.

The JCS said no unusual movements by the North Korean military have been detected so far.