The Diplomatic Security Service (DSS or DS) is the principal security and law enforcement agency of the United States Department of State. As the operational division of State Department's Bureau of Diplomatic Security, its primary mission is to protect diplomatic assets, personnel, and information and to combat visa and passport fraud. DSS also undertakes counterterrorism, counterintelligence, cybersecurity and criminal investigations, both domestically and abroad. Originating from diplomatic security measures enacted during the First World War, DSS was formally established in 1985 following the deadly 1983 bombings of the U.S. embassy and Marine barracks in Beirut, Lebanon. It is the leading U.S. law enforcement agency abroad and the most widely deployed in the world, protecting 275 U.S. diplomatic missions in over 170 countries and 29 U.S. cities. As employees of the U.S. State Department DSS special agents are unique in U.S. federal law enforcement for also being members of the Foreign Service. DSS' most visible activity is providing security to the U.S. Secretary of State, the U.S. Ambassador to the United Nations and other senior diplomats. As part of its duty to provide a safe and secure environment for U.S. diplomacy, DSS also protects foreign dignitaries, advises U.S. ambassadors on security matters, and manages security programs for international events, often in cooperation with domestic and foreign counterparts. Overview While best known for its security role, DSS is a full-fledged law enforcement agency that conducts international criminal investigations, threat analysis, counterterrorism, counterintelligence, security technology and cybersecurity. The agency employs over 2,000 special agents, sometimes referred to as "DSS Agents" or "DS Agents." These agents are federal agents with the power to arrest, carry firearms, serve arrest warrants and perform other law enforcement activities. Whereas most U.S. federal law enforcement agents are members of the Federal Civil Service, the majority of DSS special agents are both Foreign Service specialists and law enforcement officers. DSS agents are uniquely required to serve multiple-year tours abroad as a condition of employment. When not on an overseas assignment, agents serve at DSS headquarters in Arlington, Virginia, or in one of the 29 field offices nationwide. A small percentage of DSS special agents are members of the State Department's Civil Service and are not mandated to serve tours overseas; they instead focus on criminal investigations and dignitary protection within the United States. When assigned to domestic field offices, DSS special agents investigate passport fraud and visa fraud, and