The West might believe that Mosul and Raqqa are the final frontiers in the battle against the Islamic State (ISIS), but the terrorist group has, over the last six months, pulled resources and people from those frontlines to fortify the lesser-known province of Deir ez-Zor. Located in Syria’s southeast near the Iraqi border, Deir ez-Zor has been largely under ISIS control since 2014.
Conveniently located between Raqqa and Mosul, Deir ez-Zor is strategically positioned to serve as a military and supply hub for ISIS. Flanked by mountains and divided by the enormous Euphrates river, the town is a natural fortress, which will make it more difficult for ground troops to launch a surprise attack, and airstrikes alone may not be very effective.
Deir ez-Zor also holds the richest oil supply in all of Syria, which could help ISIS recover financially after losing nearly 30 percent in oil revenues and taxes from lost territory as a result of the U.S.-led offensive. And although the U.S.-led coalition had previously tried to stop oil production and trade in Deir ez-Zor, it limited its strikes to oil trucks since destroying oil fields in the region would have caused uncontrollable fires and catastrophic ecological destruction.
On top of the geographical advantages, ISIS enjoys the support of several local Iraqi-based tribes, such as those based in al Qaem, Rawah, or Anah, thanks to its clever manipulation of local tribal relations. Because several tribes in the city are separated by the Iraqi–Syrian border, ISIS effectively abolished the border and then reorganized Deir ez-Zor into two states. One state contains the cities of Mayadeen and Deir ez-Zor, the province’s namesake, as well as the northern sector, while the other covers Abu Kamal city, the southern sector, and incorporates Iraqi cities such as al Qaem. These strategies helped empower local tribal leaders who became rulers of new swaths of territories and who then threw their support behind ISIS.
In short, Deir ez-Zor is an ideal