 The 2nd Panzer Division ( XVIII Mountain Corps ) entered Yugoslavia from the east on the morning of 6 April and advanced westward through the Struma Valley . It encountered little resistance , but was delayed by road clearance demolitions , mines and mud . Nevertheless , the division was able to reach the day 's objective , the town of Strumica . On 7 April , a Yugoslav counter @-@ attack against the division 's northern flank was repelled , and the following day , the division forced its way across the mountains and overran the thinly manned defensive line of the Greek 19th Mechanized Division south of Doiran Lake . Despite many delays along the mountain roads , an armoured advance guard dispatched toward Thessaloniki succeeded in entering the city by the morning of 9 April . Thessaloniki was taken after a long battle with three Greek divisions under the command of General Bakopoulos , and was followed by the surrender of the Greek Eastern Macedonia Army Section , taking effect at 13 : 00 on 10 April . In the three days it took the Germans to reach Thessaloniki and breach the Metaxas Line , some 60 @,@ 000 Greek soldiers were taken prisoner . The British and Commonwealth forces then took over the defence of Greece , with the bulk of the Greek Army fighting to maintain their old positions in Albania . 
