Since late 2017, militias affiliated to the Iranian Revolutionary Guard Corps (IRGC) have been deployed in areas west of the Euphrates River, and parts of the region to its east in the governorate of Deir ez-Zor, which was previously under Islamic State (IS) control. Within two years of their being there, these militias from various backgrounds – foreign, Syrian and local – have succeeded in recruiting thousands of local youths into their ranks, thus providing the IRGC with important contact with the local communities. Iran is attempting to get closer to the local population and gain legitimacy with it through its civil, charitable and humanitarian activities, for which it has mainly relied on the Iranian Cultural Centre and the Jihad al-Binaa organisation. At the same time, Iran has succeeded in building important relationships and friendships with the governor of Deir ez-Zor, leaders of the regime’s intelligence services and other influential officials in the higher circles of local government. It has also succeeded, especially through the Iranian Cultural Centre, in bringing local figures from the economic, social and professional elite and official religious institutions into the diverse networks it is currently forming, which extend from Deir ez-Zor to the capital Damascus, where other Iranian institutions are active. The weakness, disintegration and exhaustion of the local communities resulting from the prolonged war in the governorate have enabled Iran to infiltrate the fabric of these communities, which have lost their ability to oppose Iranian influence, even if Iran raises sensitivities, particularly religious ones. Despite the strength and opportunities available to Iran in Deir ez-Zor, major obstacles still stand in its way. The most important of these is the sectarian disparity, given the overwhelming Sunni majority, which wishes to preserve its faith and is influenced by the prevailing Sunni view of Shiism as a deviation from original Islam. This view owes much to the Salafi-jihadism embodied by IS, which has survived as both a set of rejectionist ideas and a physical militant group still capable of launching attacks from its pocket of influence in the Syrian desert (Badia). Escalating Israeli airstrikes on IRGC positions in the governorate and the presence of US forces east of the Euphrates are other threats to Iranian influence there. Moreover, another primary challenge to Iran in the region is the strict economic sanctions imposed by the United States, which have hindered recruitment and led to the salaries of local militiamen in Deir ez-Zor being lowered.