In the west supply problems began slowing down Allied operations, even though the opening of the port of Antwerp in late November improved the situation. The positions of the Allied armies stretched from southern France all the way north to the Netherlands. The Germans wanted to attack the thin line of Allied forces. They thought this would stop Allied advances on the Western Front. Several plans for major Western attacks were prepared. A first plan was for an attack on the U.S. forces around Aachen, to encircle the U.S. Ninth Army. A second plan was for a "blitzkrieg" attack through the weakly defended Ardennes Mountains. This aimed at splitting the armies along the U.S.—British lines and capturing Antwerp.