On 22 June 1941, the German army launched Operation Barbarossa, the massive invasion of the Soviet Union. Within four weeks, the Red Army had suffered heavy losses in troops and equipment, and, in response, the Soviet Union requested assistance from the British government. The British War Office responded by establishing the "Murmansk run" to ship vital war matériel and equipment to the northern Soviet port of Murmansk. Several Canadian merchant ships took part in the Murmansk run, and Royal Canadian Navy (RCN) destroyers were assigned to escort convoys from British ports to the Soviet Union. The RCN continued to be responsible for escort duties in the North Atlantic.