 Although the Zanj had failed to take it at that time, a significant number of Basrans were subsequently killed at the Battle of the Barges, and the city was thereafter forced to rely on the Abbasid government to send troops for protection.The fall of al-Ubulla and of al-Ahwaz in 870 further instilled a state of panic in the city, and many of its inhabitants decided to evacuate to safer areas.In order to weaken Basra, the Zanj placed the city under virtual siege, harassing it with attacks day and night and destroying the surrounding villages.