Wiener Operation
On 22 March, the remnants of the 6th SS Panzer Army withdrew towards Vienna. By 30 March, the Soviet 3rd Ukrainian Front crossed from Hungary into Austria. By 4 April, the 6th SS Panzer Army was already in the Vienna area desperately setting up defensive lines against the anticipated Soviet Vienna Offensive. Approaching and encircling the Austrian capital were the Soviet 4th and 6th Guards Tank, 9th Guards, and 46th Armies.