Twenty-five South Korean officials continue to work as usual at an inter-Korean liaison office in the North Korean border city of Gaeseong, a day after North Korea withdrew all of its staff.

An official at Seoul's Unification Ministry says the South Korean side is operating in emergency mode and has doubled its usual head count at the office to nine employees and 16 support members. 

A ministry official said Seoul remains in frequent contact with the office and there are no concerns about the employees' safety. 

Before departing, North Korean representatives said Pyongyang does not mind if the South Korean side decides to stay in Gaeseong and that it would be in contact in coming days to resolve working-level matters.