Kurdish forces backed by Free Syrian Army-affiliated fighters have surrounded the strategic ISIS stronghold of Sarrin, which lies in a key position north of the militant group’s de-facto Raqqa capital.

“Intense clashes between Kurdish People’s Protection Units (YPG) fighters supported by [FSA] rebel troops on one hand and ISIS militants on the other have been ongoing for the past 48 hours in the villages surrounding Sarrin,” the Syrian Observatory for Human Rights reported late Tuesday.

The Observatory cited “trusted sources” as saying that at least 10 ISIS members have been killed in the fighting. […]