diplomatic security service
Diplomatic Security Service. A bureau of the U.S. Department of State having responsibility for protecting the Secretary of State and domestic and foreign dignitaries, as well as for investigating criminal activities such as identity-document fraud involving U.S. passports and visas. • The Service now employs some 800 special agents (members of the U.S. Foreign Service), who are located throughout the United States and in scores of embassies worldwide.