However, on 13 July Hitler called off the failed Kursk offensive; the Allies had landed in Sicily, so he issued the order for a withdrawal. Manstein protested; he felt that the Soviet forces had exhausted all their reserves in the area, and he did not want to stop until all his own reserves had been committed. Hitler, however, insisted on calling off the operation. Although Soviet casualties were indeed heavy, modern historians discount the possibility of a successful German continuation of the offensive.