The Northern Fleet (Russian: Северный флот, Severnyy Flot; named Red Banner Northern Fleet in Soviet time) is a unit of the Russian Navy responsible for the defense of northwestern Russia. The fleet has access to the Arctic and Atlantic Oceans from bases on the Barents and Norwegian Seas. The fleet headquarters and administrative center are located at the main base at Severomorsk with secondary bases elsewhere in the Kola Bay. The fleet was established as part of the Soviet Navy in 1937. The fleet operated more than 200 submarines ranging from diesel-electric attack (SS) to nuclear-powered ballistic missile (SSBN) classes during the Soviet Era.