Abd Allah ibn al-Zubayr
Iraq, and Khurasan with it, ultimately came under the suzerainty of the anti-Umayyad, Mecca-based caliph, Abd Allah ibn al-Zubayr (), who appointed al-Muhallab governor of Khurasan. Meanwhile, a mass wave of Azdi tribesmen from Oman had migrated to Basra between 679 and 680, merged with the Azd Sarat already present in the city and formed a strong alliance with the Rabi'a tribal confederation, a major faction in the Basran garrison. After Yazid's governor in the city, Ubayd Allah ibn Ziyad, was ousted in the aftermath of the caliph's death, the Azdi leader of the Azd–Rabi'a alliance, attempted to gain control of the city and was killed by members of the rival Banu Tamim, the other major faction of the Basran garrison. This precipitated hostilities between the two groups, which spread to Khurasan where troops from both factions were deployed.