After a battle in Otumba, they managed to reach Tlaxcala, having lost 870 men. With the assistance of their allies, Cortés's men finally prevailed with reinforcements arriving from Cuba. Cortés began a policy of attrition towards Tenochtitlán, cutting off supplies and subduing the Aztecs' allied cities. During the siege he would construct brigantines in the lake and slowly destroy blocks of the city to avoid fighting in an urban setting. The Mexicas would fall back to Tlatelolco and even succeed in ambushing the pursuing Spanish forces, inflicting heavy losses, but would ultimately be the last portion of the island that resisted the conquistadores. The siege of Tenochtitlán ended with Spanish victory and the destruction of the city.