Joint Chiefs of Staff(JCS) Chairman Kim Myung-soo said Thursday that North Korea is cutting off land routes connecting the two Koreas to prevent North Koreans from defecting to South Korea.

The chairman made the remarks during a parliamentary audit, calling the North’s action "unreasonable" and saying it will only isolate the country even more.

Kim showed images of North Korean troops cutting off access to inter-Korean routes, stressing that Seoul had monitored such activities in advance.

Pyongyang announced on Wednesday that it was severing all road and railway links to South Korea.

Since the end of last year, North Korea has been laying landmines in border regions and removing street lights along the blocked Donghae and Gyeongui railway lines, which connect the two Koreas.