A local radio network run by North Korean defectors says Pyongyang has implemented a new system in which it more closely monitors the cross-border passage of its citizens.

Free North Korea Radio quoted its correspondents in the North as saying Wednesday that under the new system, citizens crossing the North Korean border into China or Russia must have their identification cards and permission to depart the North on hand.

The report said the North apparently put the system in place in a bid to fully block defections and to boost border control.

The report said people who are found to be carrying no such identification or documentation when they cross the border will be taken into custody for interrogation and will be subject to fines.