Eisenhower had then wanted Montgomery to go on the offensive on 1 January to meet Patton's army that had started advancing from the south on 19 December and in doing so, trap the Germans. However, Montgomery refused to commit infantry he considered underprepared into a snowstorm and for a strategically unimportant piece of land. He did not launch the attack until 3 January, by which point the German forces had been able to escape. A large part of American military opinion thought that he should not have held back, though it was characteristic of him to use drawn-out preparations for his attack. After the battle the U.S. First Army was restored to the 12th Army Group; the U.S. Ninth Army remained under 21st Army Group until it crossed the Rhine.