The effect on the morale of German troops caught up in a Typhoon RP and cannon attack was decisive, with many tanks and vehicles being abandoned, in spite of superficial damage, such that, at Mortain, a signal from the German Army's Chief of Staff stated that the attack had been brought to a standstill by 13:00 '...due to the employment of fighter-bombers by the enemy, and the absence of our own air-support.' The 20 mm cannon also destroyed a large number of (unarmoured) support vehicles, laden with fuel and ammunition for the armoured vehicles. On 10 July at Mortain, flying in support of the US 30th Infantry Division, Typhoons flew 294 sorties in the afternoon that day, firing 2,088 rockets and dropping of bombs. They engaged the German formations while the US 9th Air Force prevented German fighters from intervening. Dwight D. Eisenhower, the Supreme Allied Commander, said of the Typhoons; "The chief credit in smashing the enemy's spearhead, however, must go to the rocket-firing Typhoon aircraft of the Second Tactical Air Force... The result of the strafing was that the enemy attack was effectively brought to a halt, and a threat was turned into a great victory."