 On August 31 Burayh was informed that the Zanj leader had sent money and supplies into the desert to raise a force among the Arab tribes, and that a combined force of Zanj infantry and Arab horsemen were planning to attack Basra.Approximately a week later, the Arabs in Basra received a warning from members of the Banu Tamim and Banu Asad that were cooperating with the Zanj, informing them that they and the Zanj would be attacking the next day and that they should evacuate their women and children before the city was surrounded.Burayh responded to this news by advancing outside the city and setting up a defensive force at a trench, but when 'Ali ibn Aban approached his position he lost his nerve and returned to Basra, allowing 'Ali to continue toward the city unopposed.