Syria’s Western-backed opposition coalition said an Islamist militant group with ties to al-Qaeda has switched from fighting President Bashar al-Assad’s forces to battling for control of rebel-held territories.

The presence of al-Qaeda-linked militants from the Islamic State in Iraq and the Levant in “liberated areas, poses a threat to civilians,” the Syrian National Coalition said in a statement on its website. The statement came after clashes between the militants and the Western-backed Free Syrian Army for control of the northern town of Azaz.