The attack, when it came, completely surprised the Allied forces. The U.S. Third Army intelligence chief, Colonel Oscar Koch, the U.S. First Army intelligence chief and the SHAEF intelligence officer had warned that the Germans might attack the U.S. VIII Corps area. These warnings were ignored by the U.S. 12th Army Group. Because the Ardennes was considered a quiet sector, the Allies used it as a training ground for new units and a rest area. The U.S. units deployed in the Ardennes thus were a mixture of inexperienced troops (such as the U.S. 99th and 106th "Golden Lions" Divisions), and veteran troops sent to that sector to rest (the 28th Infantry Division).