The National Police Agency's Security Bureau formulates and supervises the execution of security policies. It conducts research on equipment and tactics for suppressing riots and oversaw and coordinates activities of the riot police. The Security Bureau is also responsible for security intelligence on foreigners and radical political groups, including investigation of violations of the Alien Registration Law and administration of the Entry and Exit Control Law. The bureau also implements security policies during national emergencies and natural disasters. The National Police Agency's First Public Safety Division investigates radical leftists.
A secret unit in the Japanese National Police Agency was set up to deal with contingencies related to North Korea. It has recruited and trained North Koreans to gather intelligence on Japan's behalf. According to some reports, high-ranking members of Chosen Soren, the North Korean residents' organization in Japan, have been recruited to work for Japan, performing such tasks as exposing North Korean agents.