In fighting over the weekend, ISIS forces seized the town of Soran Azaz and some nearby villages from a rival rebel faction, putting them on the outskirts of the important city of Azaz and the accompanying border crossing into Turkey.
Control over border crossings has long been a major goal for rebel factions in the Syrian Civil War, as whoever controls a crossing can demand a portion of any arms smuggled in by rival factions through that route. ISIS already has a substantial portion of the Syria-Turkey border, as well as virtually the whole Syria-Iraq border.
Turkey has long been the go-to smuggling route for rebels, with Turkish spy agencies not only looking the other way, but even providing some arms of their own to Islamist rebels factions, a scandal that has been the subject of growing concern among Turkish prosecutors.
It’s perhaps unsurprising that ISIS should control so many of Syria’s border crossings, as they hold over half of the country at this point. Their gains nationwide continue to mount, and the Assad government’s own territory continues to shrink.