As each side converges on the Islamic State-held city of al-Bab, a military confrontation between Turkish-led rebels and pro-regime forces appear inescapable. In the meantime, tensions between Ankara and Moscow are rising yet again, risking pulling the United States and NATO further into the Syrian theater.
Jaysh al Tahrir, a group that has received several US TOW anti-tank missiles in the past, fought with the Kurdish-led Syrian Democratic Forces (SDF) in northern Aleppo. The SDF is the main anti-Islamic State fighting force for the United States and has received considerable support from the West.
Despite being forced largely underground in Iraq, Ansar al Islam continues to operate in Syria against regime and now Kurdish forces.