Federal Counterintelligence Service followed by Federal Security Service
The Federal Counterintelligence Service of the Russian Federation (FSK RF; Russian: Федеральная служба контрразведки Российской Федерации, romanized: Federal'naya sluzhba kontrrazvedki Rossiskoy Federatsii) was the main security agency of Russia. The FSK was the main successor agency to the Soviet Union's KGB. It existed from 1993 to 1995, when it was reorganized into the Federal Security Service (FSB).