Due to the Mongol invasion, the sacking of Samarkand and being deserted by his Afghan allies, Jalal ad-Din was forced to flee to India. At the Indus River, however, the Mongols caught up with him and slaughtered his forces, along with thousands of refugees, at the Battle of the Indus. He escaped and sought asylum in the Sultanate of Delhi but Iltutmish denied this to him in deference to the relationship with the Abbasid caliphs. The cities of Herat, Ghazni and Merv were destroyed and massacred by the Mongols, for his resistance or rebelliousness.