The strategic nuclear-powered submarines represented a part of the nuclear power of the Soviet Union. Nuclear-powered hunter-killers were able to advance to the Atlantic Ocean to attack US carrier groups. Ships, especially the large numbers of cruisers and destroyers and later on single numbers of aircraft carriers were mainly commanded to defend their home bases and surrounding territories. The amphibious forces could have been used to attack NATO territory close by, such as Northern Norway. Relocating the main naval powers in the Barents Sea was a huge strategic success. Hence the NATO was forced to use extended naval powers on securing their sea routes to avoid being cut off from Northern American enforcements and supplies in case of the outbreak of a war. However, it was very costly for the Soviet Union to build up and maintain those bases far away from they own industry and under extreme weather conditions.