The US has accused the Syrian government of providing air support to an advance by Islamic State militants against opposition groups north of Aleppo.
Fighters opposing the Syrian president, Bashar al-Assad, have made the same claims since Sunday, when Isis began advancing towards the town of Azaz near the Turkish border.
Fighters opposing the Syrian president, Bashar al-Assad, have made the same claims since Sunday, when Isis began advancing towards the town of Azaz near the Turkish border.
