 This constituted a deep salient east into Soviet lines and was subject to outflanking attempts on the corps left flank; Soviet armoured units had already appeared 20 miles behind the corps front line.XI Army Corps now made a series of phased withdrawals toward Kharkov to prevent encirclement.Only reaching the final defenses north of the city on 12 August 1943, following breakthroughs by the 57th and 69th Armies in several sectors of the front-line, the disintegration of the 168th Infantry Division and after an intervention by the corps reserve.