A rebel group backed by Turkey will send reinforcements to the front lines of the last major rebel enclave in northern Syria to oppose a government offensive, it said on Thursday.

Over the past week, the Syrian army has advanced toward the town of Khan Sheikhoun in Idlib in a pincer movement that could encircle the southern part of the rebel enclave.

The British-based Syrian Observatory for Human Rights said on Thursday that the rebels had launched a counterattack on the eastern pincer at the village of Sukeik, and that dozens had been killed in the fighting.