By circa 686, Zufar's participation in the Qaysi–Yamani conflict in the Syrian Desert was highly restricted by persistent campaigns against his safe haven at al-Qarqisiyah by the Umayyad caliph Abd al-Malik (r. 685–705); Zufar was replaced in this regard by Umayr ibn al-Hubab of the Banu Sulaym.[12] Umayr's Sulaymi tribesmen began encroaching on the lands of the Banu Taghlib along the northern Khabur Valley, prompting the Banu Taghlib to request Zufar intervene and force the Banu Sulaym to withdraw from the area.[12] Not wanting to push the neutral and Christian Banu Taghlib into joining the Umayyad–Yamani cause, Zufar attempted but failed to calm the situation.[13] Umayr opened hostilities against the Banu Taghlib in a number of punishing raids in Upper Mesopotamia, and dragged Zufar into assisting him in some of these clashes.[14] Umayr was killed by the Banu Taghlib in 689, obliging Zufar to avenge his death.[14] To that end, Zufar attacked a Taghlibi camp at the northern Tigris River town of Kuhail and executed two hundred Taghlibi captives taken in that raid.[15] Referencing this event, the poet Jarir taunted his Taghlibi rival al-Akhtal, stating: