Using his new-found power, Salih captured the Euphrates towns of Manbij and Balis, located east and southeast of Aleppo, respectively. With these conquests and his control of al-Rahba, Salih established what would become the Upper Mesopotamian portion of the Mirdasid emirate. This crossroads region was agriculturally, commercially and strategically valuable, and put Salih in contact with the Byzantines, the Fatimids and the rulers of Iraq. Meanwhile, the agreement between Salih and Mansur collapsed as the latter abandoned most of his promises, including giving his daughter's hand in marriage and according the Kilab their share of Aleppo's revenues. Salih retaliated by besieging Aleppo, while the Kilab and their Bedouin allies plundered the countryside. Mansur appealed for Byzantine intervention and warned the Byzantine emperor, Basil II (), that if left unchecked, the Bedouin uprising could spread to his territory. Basil dispatched 1,000 Armenian relief troops in response, but withdrew them after Salih informed him of Mansur's treachery and pledged his goodwill to the Byzantines. Basil may have also acquiesced to Salih's activities to avoid provoking Bedouin raids against his territory, which bordered the emirates of both the Kilab and their Numayri kinsmen. The withdrawal of Byzantine troops weakened Mansur's position further and strengthened Salih, who dispatched one of his sons to Constantinople to pay allegiance to Basil.