Advances on IS Strongholds Underlines US, Russia Convergence

The Syria Democratic Forces — a mixed-religion anti-IS coalition made up of Kurdish and Arab groups — is dominated by the YPG. The U.S. provides critical air support to the SDF, and hundreds of U.S. special operation forces help train the group. Russia has also offered support to the Kurds, partly to gain leverage over Turkey, which considers the PYD to be a terrorist group.