During World War II, casemate-type armoured fighting vehicles were heavily used by both the combined German Wehrmacht forces, and the Soviet Red Army. They were mainly employed as tank destroyers and assault guns. Tank destroyers, intended to operate mostly from defensive ambush operations, did not need a rotating turret as much as offensively used tanks, while assault guns were mainly used against fortified infantry positions and could afford a longer reaction time if a target presented itself outside the vehicle's gun traverse arc. Thus, the weight and complexity of a turret was thought to be unnecessary, and could be saved in favour of more capable guns and armour. In many cases, casemate vehicles would be used as both tank destroyers or assault guns, depending on the tactical situation. The Wehrmacht employed several casemate tank destroyers, initially with the still-"Panzerjäger" designation "Elefant" with an added, fully enclosed five-sided (including its armoured roof) casemate atop the hull, with later casemate-style tank destroyers bearing the "Jagdpanzer" (literally 'hunting tank') designation, with much more integration of the casemate's armour with the tank hull itself. Examples are the Jagdpanzer IV, the Jagdtiger and the Jagdpanther (the latter two translate as 'Hunting Tiger' and 'Hunting Panther', respectively). Assault guns were designated as 'Sturmgeschütz', like the Sturmgeschütz III and Sturmgeschütz IV. In the Red Army, casemate tank destroyers and self-propelled guns bore an "SU-" or "ISU-" prefix, with the "SU-" prefix an abbreviation for Samokhodnaya Ustanovka, or "self-propelled gun". Examples are the SU-100 or the ISU-152. Both Germany and the Soviet Union mainly built casemate AFVs by using the chassis of already existing turreted tanks, instead of designing them from scratch.