Syrian army prepares assault as IS battles insurgents

Islamic State militants battled rival insurgent groups on Wednesday north of the city of Aleppo, where officials say the Syrian army is preparing an offensive of its own backed by Iranian soldiers and Russian jets.

A rebel fighter and a group monitoring the war said Islamic State fighters took control of parts of the towns of Ahras and Tel Jabin, about 12 km north of Aleppo, before being pushed back.

Gains by Islamic State north of Aleppo would threaten the supply lines of rival rebels inside the city, which is divided between insurgents and government forces. The Syrian Observatory for Human Rights said the road used by Aleppo residents heading north to the Turkish border remained closed on Wednesday.

The Observatory reported fighting between Islamic State fighters and government forces trying to advance towards an air base besieged by the jihadist group in Aleppo province.

Any further escalation in the Aleppo area near the Turkish border will likely further anger NATO member Ankara which opposes President Bashar al-Assad, backs the insurgents, and has expressed deep concern at Russian air strikes.