An influential former presidential official was arrested for playing a role in the illegal political surveillance of politicians, government officials and outspoken civilian figures.
Woo Byung-woo, who served as a top presidential aide to jailed ex-president Park Geun-hye, was jailed on early Friday after a court issued an arrest warrant at the request of prosecutors on charges of abusing power.
Woo, 50, has been already on trial without detention for his alleged role in a corruption scandal involving Park's crony, Choi Soon-sil. He is accused of ordering the National Intelligence Service (NIS) to put selected government officials and others under secret surveillance.
NIS officials have been arrested for creating a watch list of actors, film directors, columnists and singers.