The White Sea Flotilla replaced the Arctic Sea Flotilla and was renamed as the Naval Forces of the North Sea, but was later disbanded in January 1923. Soviet Navy Northern Flotilla The Northern Flotilla was formed on August 5, 1933, by transferring patrol boats Smerch and Uragan, D-class submarines Dekabrist (D-1) and Narodovolyets (D-2) and two destroyers from the Baltic Fleet to Northern Russia. These ships departed from Kronstadt on 18 May 1933 and arrived at Murmansk on 5 August. Another destroyer, another patrol boat, another submarine, and two minesweepers joined the flotilla at Soroka in September 1933. Polyarny became the flotilla's main base, and a flight of MBR-2 flying boats joined the unit at Murmansk in September 1935. The Northern Flotilla was quickly expanded in the years after it was formed, receiving new ships, airfields, coastal and air defence artillery. On May 11, 1937, the fleet entered its current form when it was renamed to the Northern Fleet (Северный флот, Severnyy flot). World War II The Northern Fleet blocked the Finnish military base at Petsamo through the Winter War of 1939 and 1940. By June 1941, the fleet included 8 destroyers, 15 submarines, 2 torpedo boats, 7 patrol boats, 2 minesweepers, and 116 airplanes. In August 1940, the Soviets created the White Sea Military Base to defend the coastline, bases, ports, and other installations. The White Sea Flotilla was established in August 1941 under the command of Rear-Admiral M. Dolinin. Subsequent commanders were Vice Admiral Georgy Stepanov (in October), Rear-Admiral Stepan Kucherov, and Vice-Admiral Yuriy Panteleyev. During the German-Soviet War of 1941 to 1945, the Northern Fleet defended the coastlines of the Rybachy and Sredny peninsulas, secured internal and external transportation routes, and provided support to the maritime flank of the 14th Army. Naval Infantry and up to 10,000 Northern Fleet personnel participated in land warfare including the Petsamo-Kirkenes Operation of 1944. Northern Fleet Naval Infantry units caused tens of thousands of German casualties fighting during the Moscow, Leningrad, Stalingrad, and North Caucasus campaigns. Among the air units of the Northern Fleet was the 121st Fighter Aviation Regiment. The Northern Fleet was reinforced with naval aircraft and ships from the Pacific Ocean and Caspian Sea. Great Britain and the United States temporarily provided HMS Royal Sovereign and to the USSR in exchange for the Italian ships captured during the war and destined to be divided among the allies. During