Isil fighters advance on Syria’s Aleppo after Russian air strikes in ‘most significant attack’

Islamic State of Iraq and the Levant (Isil) militants reached the outskirts of Syria’s second city on Friday as the US warned Russia that its campaign to tackle the extremist group was backfiring.

The jihadists launched a surprise attack on non-Isil rebel positions north of Aleppo on Thursday night, seizing at least three villages and a former army base that rebels had captured from troops loyal to President Bashar al-Assad two years ago.

The attack brought them close to regime positions in the north-east of the city. Further advances could mean rebels, including many characterised as “moderate” by the West, become sealed inside the besieged city by a circle of regime and Isil fighters.