With the Italians bogged down in the war with Greece and the Allies sending troops to aid them, Hitler decided to intervene on the Italian side. The Germans combined their attack on Greece with their attack on Yugoslavia. The Germans attacked on April 6th. At the time most of the Greek army was deployed on the Albanian border engaging the Italian army. The German attacked simultaneously by air and the ground. From the ground they attacked from Bulgaria where the Italian had few troops. The German quickly overran the Metaxas defensive line. The number of British, Australian and New Zealand troops were not large enough to stop the Germans. The Allied forces withdrew to the Thermopylae position which was the defensive line for Athens and held it for a few days allowing the withdrawal of Allied troops to the beaches. Athens fell to the Nazis on April 27th and the southern shores of Greece were reached on April 30th were they captured 7,000 Allied forces who had not been evacuated.