Attritional air battle alarmingly depleted the Luftwaffe's strength. 911 aircraft were lost in July, while inflicting much heavier losses on the Soviet Air Forces, whose strength appeared to be undiminished. The Soviet 11th Guards Army initiated an offensive aimed at cutting off the 2. "Panzerarmee" and German 9th Army. The Luftwaffe was called upon to rescue the situation in a huge aerial counter-offensive lasting from 16 July–31 July against a Soviet offensive at Khotynets and saved two German armies from encirclement, reducing the attacking Soviet 11th Guards Army to just 33 tanks by 20 July. The Soviet offensive had been completely halted from the air Model sent a message to von Greim thanking him, stating "the "Luftwaffe's " intervention was absolutely decisive to prevent a second, more disastrous Stalingrad".