Eisenhower took direct command of all Allied ground forces on 1 September. Concerned about German counter-attacks and the limited materiel arriving in France, he decided to continue operations on a broad front rather than attempting narrow thrusts. The linkup of the Normandy forces with the Allied forces in southern France occurred on 12 September as part of the drive to the Siegfried Line. On 17 September, Montgomery launched Operation Market Garden, an unsuccessful attempt by Anglo-American airborne troops to capture bridges in the Netherlands to allow ground forces to cross the Rhine into Germany. The Allied advance slowed due to German resistance and the lack of supplies (especially fuel). On 16 December the Germans launched the Ardennes Offensive, also known as the Battle of the Bulge, their last major offensive of the war on the Western Front. A series of successful Soviet actions began with the Vistula–Oder Offensive on 12 January. Hitler committed suicide on 30 April as Soviet troops neared his "Führerbunker" in Berlin, and Germany surrendered on 7 May 1945.