The Defense Clandestine Service (DCS) is an arm of the Defense Intelligence Agency (DIA), which conducts clandestine espionage activities around the world to answer national-level defense objectives for senior U.S. policymakers and military leaders. Staffed by civilian and military personnel, DCS is part of DIA's Directorate of Operations and works in conjunction with the Central Intelligence Agency's Directorate of Operations and the U.S. military's Joint Special Operations Command. DCS consists of about 500 clandestine operatives, which is roughly how many case officers the CIA maintained in the early 2000s prior to its expansion.