||This article relies largely or entirely upon a single source. (March 2013)
is an attack submarine.
An attack submarine or hunter-killer submarine is a submarine specifically designed for the purpose of attacking and sinking other submarines, surface combatants and merchant vessels. They are also used to protect friendly surface combatants and missile submarines. Some attack subs are also armed with cruise missiles mounted in vertical launch tubes, increasing the scope of their potential missions to include land targets.
Attack submarines may be either nuclear-powered or diesel-electric ("conventionally") powered. In the United States Navy naming system, nuclear-powered attack submarines are known as SSNs and their diesel-electric predecessors were SSKs.