 Kluge ordered the attack to be mounted on the night of 6 / 7 August . To avoid alerting American forces to the attack , there would be no preparatory artillery bombardments . The intention was to hit the U.S. 30th Infantry Division , commanded by Major @-@ General Leland Hobbs , east of Mortain , then cut through American defenses to reach the coast . Had surprise been achieved , the attack might well have succeeded , but Allied decoders at Ultra had intercepted and decrypted the orders for Operation Lüttich by August 4 . As a result , Bradley was able to obtain air support from both the US 9th Air Force and the RAF . 
