The National Police of Iran operated with approximately 200,000 men in 1979, a figure that has not fluctuated much since. The National Police was also under the Ministry of Interior, and its responsibilities included all cities with more than 5,000 in population, at least 20 percent of the population. Additionally the National Police was responsible for passport and immigration procedures, issuance and control of citizens' identification cards, driver and vehicle licensing and registration, and railroad and airport policing. Some of these duties were absorbed into the Ministry of the Pasdaran during the early years of the Revolution, and cooperation between these two branches seemed extensive.