"More than 270 actively operating agents and 70 foreign intelligence recruits, including 35 Russians, have been exposed since 2003," FSB Head Nikolai Patrushev told Russian popular weekly Argumenty i Fakty.
Patrushev added that 14 agents and 33 recruits, including active as well as retired Russian soldiers, have been caught this year alone; most have been sentenced to prison terms.
Patrushev also accused Washington and London of using spies from Poland, Georgia and the Baltics to spy in Russia.
"This concerns a wide spectrum -- from staff composition and budget allocations to strategic guidance and organization of joint operations," he said.
The West aims to find out military secrets concerning Russia’s missile program and to influence domestic politics, Patrushev said.
In Russia, authorities have targeted several NGOs because Moscow believed they were financing “destabilizing” political groups.
Britain has rowed with Russia in the past over the killing of former Russian spy Alexander Litvinenko, who was poisoned while in exile in London.