Syria: Clashes among Syria fighters pose challenge for Turkey and US
Groups that have received support from the United States or its allies have turned their guns on each other in a northern corner of Syria, highlighting the difficulties of mobilizing forces on the ground against the Islamic State in Iraq and the Levant (ISIL).
As they fought among themselves before reaching a tenuous cease-fire on Thursday, ISIL meanwhile edged closer to the town of Azaz that was the focal point of the clashes near the border with Turkey.
Combatants on one side are part of a new US-backed alliance that includes a powerful Kurdish militia, and to which Washington recently sent military aid to fight ISIL.
Their opponents in the flare-up include rebels who are widely seen as backed by Turkey and who have also received support in a US-backed aid program.