Almost four years into the American-backed campaign to defeat the Islamic State group in Syria, the jihadi group is all but decimated. It's cornered into a tiny sliver of territory in Eastern Syria.

The U.S.-sponsored Syrian Democratic Forces (SDF), a coalition of Kurdish and Arab militias, has the jihadists surrounded in the most contested territory in Syria: Deir Ezzor province. And the local Arab Deir Ezzor Military Council — backed by U.S. and French special forces — are leading the battle.

But the struggle for control of Deir Ezzor isn't over yet.

The neglected region is home to Syria's largest oil fields and straddles strategic supply routes to Iraq. As the Islamic State collapses, the SDF and its American backers find themselves maneuvering for control with the Assad-loyalist Syrian Arab Army, and the powerful countries behind it, Russia and Iran.

Control of this resource-rich and strategically important region will be a powerful asset in any future peace negotiations, but like the rest of the SDF, the Deir Ezzor Military Council doesn't know how long the American government intends to stay in the region — and what will happen if the U.S. pulls out.

This segment originally aired June 4, 2018 on VICE News Tonight on HBO.