II SS Panzer Corps
After Operation Spring Awakening, the 6th SS Panzer Army withdrew towards Vienna and was involved what became known as the Vienna Offensive. The only major force to face the attacking Red Army was the II SS Panzer Corps (2 SS "Das Reich" and 3 SS "Totenkopf"), under the command of Wilhelm Bittrich, along with "ad hoc" forces made up of garrison and anti-aircraft units. Vienna fell to the Soviet forces on 13 April. Bittrich's II SS Panzer Corps had pulled out to the west that evening to avoid encirclement. The LSSAH retreated westward with less than 1,600 men and 16 tanks remaining.