The Russian Defense Ministry says a new chief has been appointed to the country's largest spy agency, the GRU military intelligence service.

Major General Igor Sergun was named head of the General Staff Main Intelligence Directorate on Monday. He replaces outgoing GRU chief Alexander Shlyakhturov, who was said to have reached retirement age.

Shlyakhturov headed up the GRU since being appointed to the position in 2009.

The GRU came into existence in 1918, and unlike the KGB secret police during the Soviet-era, did not dissolve or change its name following the break-up of the Soviet Union.