The public security functions of the Ministry of Internal Affairs included passport and immigration control, prison administration, fire service, and oversight of compliance with certain commercial and civic regulations. Immigration control was regarded as important and such steps as expulsions, expanded border controls, and acquisition of surveillance and communications equipment, and of weapons for immigration officers had been taken to enforce immigration laws. Immigration offices training schools were located in Kano, in Lagos, and at state headquarters. In 1983 the main ministry staff consisted of about 5,300 persons the Immigration Department employed about 2,900, the Fire Service Department 900, and the Nigerian Prisons Service 23,000. In August 1988, the authority to arrest and detain suspects without trial, formerly assigned to the chief of General Staff and to the inspector general of police, was extended to the Ministry of Internal Affairs. The ministry also had a paramilitary Security and Civil Defence Force, whose size, mission, and organization were unknown. In August 1989, it was announced that this unit was to be reorganized.

Data as of June 1991