As the 12th Army Group continued to push east towards Berlin, the 6th Army Group received orders to push into southern Germany and into Austria.[4] Despite the heavier resistance from the German Army in the south as compared to the north, the US 7th Army broke out of its bridgehead on the Rhine south of Frankfurt on 28 March. After fierce fighting, the 7th Army captured Aschaffenburg in Bavaria on 3 April and Heilbronn in Württemberg on 12 April, which left Nuremberg wide open to American attack. On 12 April the German High Command ordered the unconditional defense of all cities and Hitler placed Reich Defense Commissioner and Gauleiter of Franconia Karl Holz in charge of the German forces around Nuremberg.[2] On 15 April the 7th Army advanced towards Nuremberg, rapidly capturing Bamberg in the process.[4] As the 7th Army neared Nuremberg, Holz ordered setting up anti-tank barriers as well as anti-aircraft guns around the old city.