In the Soviet Navy, cruisers formed the basis of combat groups. In the immediate post-war era it built a fleet of gun-armed light cruisers, but replaced these beginning in the early 1960s with large ships called "rocket cruisers", carrying large numbers of anti-ship cruise missiles (ASCMs) and anti-aircraft missiles. The Soviet combat doctrine of saturation attack meant that their cruisers (as well as destroyers and even missile boats) mounted multiple missiles in large container/launch tube housings and carried far more ASCMs than their NATO counterparts, while NATO combatants instead used individually smaller and lighter missiles (while appearing under-armed when compared to Soviet ships).