The Federal Security Service of the Russian Federation is the principal security agency of Russia and the main successor agency to the Soviet Union's KGB; its immediate predecessor was the Federal Counterintelligence Service (FSK) which was reorganized into the FSB in 1995. The three major structural successor components of the former KGB that remain administratively independent of the FSB are the Foreign Intelligence Service (SVR), the Federal Protective Service (FSO), and the Main Directorate of Special Programs of the President of the Russian Federation (GUSP).
Headquarters of the FSB on 24 Kuznetski Most
Future President of Russia and former KGB officer Vladimir Putin served as the FSB's director from 1998 to 1999
President Putin meeting with Director of FSB Nikolai Patrushev on 9 August 2000
FSB special forces members during a special operation in Makhachkala, as a result of which "one fighter was killed and two terrorist attacks prevented" in 2010
A security agency is a governmental organization that conducts intelligence activities for the internal security of a nation. They are the domestic cousins of foreign intelligence agencies, and typically conduct counterintelligence to thwart other countries' foreign intelligence efforts.
The headquarters of the Finnish Security Intelligence Service or SUPO in Punavuori, Helsinki
Estonian KAPO headquarters in Kassisaba, Kesklinn, Tallinn