ISLAMIC STATE (Isis) militants launched an attack on a major military airbase in eastern Syria yesterday morning, activists said.

The assault, seen as a bid to wipe out the government's last outpost in the extremist-dominated region, began under cover of darkness with a suicide car bombing at a Syrian military position on the airfield's outskirts.

At least 19 government troops and seven Isis militants were killed in the fighting, according to the Britain-based Syrian Observatory for Human Rights.

The base outside the city of Deir el-Zour is a key military facility for President Bashar al-Assad, giving his warplanes a hub from which to bomb Isis-held cities and towns across much of eastern Syria.

The reports emerged as Mr Assad criticised US-led air strikes targeting Isis in his country as neither serious nor effective.

In a Paris Match interview he also accused Turkey of continuing to provide direct support to the militants.

He suggested that only his forces were capable of defeating Isis. "You can't end terrorism with aerial strikes. Troops on the ground that know the land and can react are essential," Mr Assad said.

"That is why there haven't been any tangible results in the two months of strikes led by the coalition."

"We are running the ground battles against Isis and we have noticed no change, especially with Turkey providing direct support to these regions," he said.

Both Mr Assad's forces and the US have been bombing Islamic State group targets in northern Syria, although US officials claim they are not co-ordinating strikes with Damascus.