The Syrian army hit back after a major Isis counteroffensive yesterday, hours after a new ceasefire between government forces and Western-backed insurgent factions came into effect.

Troops regained several towns and an airbase overrun by Isis in Thursday’s counterattack along a 100-mile front stretching from Sukhnah, east of Palmyra, to the eastern city of Deir Ezzor.

The M20 motorway was reopened after B’ir Ghabaghib and al-Shoula were retaken with support from attack jets and helicopters.