North Korea Thursday freed a South Korean worker it detained for more than four months on charges of denouncing its political system.

A Unification Ministry spokeswoman said the worker, identified only as Yu, was on his way back home from North Korea.

The Hyundai Asan employee has been held by North Korea since late March. He worked at an industrial zone in the North's border city of Gaeseong where more than 100 South Korean factories are in operation employing North Korean workers.

Hyundai Group Chairwoman Hyun Jung-eun drove to North Korea Monday to secure the release of the worker. She is due to return to the South Friday.