Efforts to brand the invasion of Raqqa as a broad-based coalition, as opposed to just a Kurdish invasion of the ISIS capital, appear to be crumbling, with the Thuwar ar-Raqqa, the main Arab group involved in the Syrian Democratic Forces (SDF) invasion, formally withdrawing from the group today.

The SDF is overwhelmingly just the Kurdish YPG with a handful of tiny affiliates, created mainly to allow them to argue invasions of ISIS territory don’t amount to an expansion of Syrian Kurdistan. The Thuwar ar-Raqqa would’ve been particularly useful to that effect, as a local force within Raqqa.

The group however, is arguing that the Kurdish forces had reneged on an agreement on the Raqqa invasion, in which the Kurdish YPG would let them “lead” the operation, and retain control of the city afterward. Instead, they say the US and the YPG have moved to sideline them.

Now they say they aren’t going to participate in the invasion at all, and that the “SDF” forces attacking Raqqa are exclusively the Kurdish YPG. This is likely to add to concern about Kurdish territory expansion, particularly by Turkey.