Smoke billows above the rebel-controlled town of Binnish near the regime-held town of Saraqeb, in the eastern part of the Idlib province in northwestern Syria, on Wednesday, during air stikes by pro-regime forces. Photo: AFP

Syrian rebels on Thursday retook a key town in northwestern Syria that they had lost earlier this month, effectively reversing an important gain for Pro-Assad forces' devastating offensive in the region.

The counteroffensive, however, may be short-lived and Russian-backed Syrian troops continue to chip away at other rebel occupied areas, ignoring growing appeals for a ceasefire.

The UN Security Council, where Moscow has systematically vetoed truce initiatives, was due to meet again on Thursday amid growing concern Idlib was witnessing the nine-year-old war's worst humanitarian emergency yet.

On Thursday, jihadists and Turkish-backed rebels managed to reenter Saraqeb, a key crossroad town in Idlib province that they had conceded earlier in February.

State news agency SANA acknowledged there were "fierce clashes" between the army and "terrorist groups on the Saraqeb front."

An AFP correspondent accompanied the rebels into Saraqeb, where he found a ghost town of bombed out buildings deserted by inhabitants.

The counterattack by the rebels temporarily backpedals one of the key areas gained by the government since the launch of its offensive against the country's last rebel-held enclave.

The cash-strapped government has been keen to fully secure the M5, a highway which connects Syria's four main cities passing through Saraqeb.

State media accused the "terrorists" of orchestrating car bombings and other suicide attacks against government forces attempting to retake the outpost.

It also added that the army had inflicted heavy losses on the attackers, despite military support coming from neighboring Turkey.

The UN has warned repeatedly that the fighting in Idlib has the potential to create the most serious humanitarian crisis since the start of the civil war in 2011.

"As the UN Security Council meets today, it is urgent for Council members to adopt a resolution calling for a ceasefire in Idlib," David Miliband, the chairman of the International Rescue Committee, said.

More than half a million of those displaced since December are children, tens of thousands of whom are sleeping rough in the harsh winter of northern Syria.

AFP