The Spruance-class destroyer USS Deyo (DD 989) conducts underway operations in support of Operation Iraqi Freedom. Deyo was one of many U.S. Navy surface combatants to fire Tomahawk Land Attack Missiles (TLAMs) in support of Operation Iraqi Freedom. Destroyers operate in support of carrier battle groups, surface action groups, amphibious groups and replenishment groups. Destroyers primarily perform anti-submarine warfare duty.. The addition of the Mk-41 Vertical Launch System or Tomahawk Armored Box Launchers (ABLs) to many Spruance-class destroyers has greatly expanded the role of the destroyer in strike warfare.