Updated

Syria's opposition National Coalition on Friday condemned attacks by Al-Qaeda loyalists of the Islamic State of Iraq and the Levant (ISIS) on mainstream rebels of the Free Syrian Army.

"The Coalition condemns the aggressions against the forces of the Syrian revolution and the repeated disregard for the lives of Syrians, and considers that this behaviour runs contrary to the Syrian revolution and the principles it is striving to achieve," a statement said.

The group denounced in particular ISIS's seizure of the town of Azaz on the border with Turkey on Wednesday after an hours-long firefight with FSA fighters and its attempt to take control of the Bab as-Salameh border crossing.

It accused ISIS of "repeated repressive practices against the freedom of civilians, doctors, journalists and political activists in recent months".

It also accused it of having "links to foreign agendas" and of seeking to create a "new state inside the Syrian state entity in violation of national sovereignty".

Azaz was one of the first towns to be overrun, in July 2012, by FSA rebels, who set up their own administration.

Tensions between FSA loyalists and ISIS have spiralled in recent months, especially in northern Syria where the opposition controls vast swathes of territory.