Syrian government forces recaptured a strategic northwestern highway town from jihadist and allied rebels Wednesday, in the latest blow to the country's last major opposition bastion.

Once a hotspot for anti-government protests, Maaret al-Numan has been turned into a ghost town by deadly regime and Russian air strikes that killed another 11 civilians in the embattled province of Idlib on Wednesday, according to a war monitor.

The town lies on the key M5 highway connecting the capital Damascus to second city Aleppo, long in the sights of the government as it seeks to revive a moribund economy ravaged by almost nine years of war.

Syrian troops pass through a recaptured village in their final push on the strategic highway town of Maaret a-Numan, held by the rebels for seven years
Syrian troops pass through a recaptured village in their final push on the strategic highway town of Maaret a-Numan, held by the rebels for seven years SANA / -

"Our forces managed in the past few days to stamp out terrorism in many villages and towns," including Maaret al-Numan, an army spokesman said.

Russian and regime air strikes on Wednesday killed 10 civilians further north in the village of Kafr Lata and another near the town of Saraqeb, also on the M5, the Syrian Observatory for Human Rights said.

It added that regime forces advancing on Saraqeb, 27 kilometres (17 miles) north of Maaret al-Numan, had seized an additional five villages.

In 2011, Maaret al-Numan was one of the first towns in the northwestern province of Idlib to rise up against the Damascus government.

Tens of thousands of Syrian civilians have fled the government's advance
Tens of thousands of Syrian civilians have fled the government's advance AFP / Omar HAJ KADOUR

The following year, it was captured by rebels fighting against President Bashar al-Assad's rule.

It is the latest town to fall in a Russian-backed offensive on the Idlib region this year.

The region, which hosts some three million people, is dominated by jihadists from Syria's former Al-Qaeda affiliate, but allied rebels are also present.

The government has slowly chipped away at the south of the bastion, despite several deals between government ally Russia and rebel backer Turkey intended to avert a broad military offensive.

Map locating Maaret al-Numan, recaptured by Syrian government forces, the army said on Wednesday.
Map locating Maaret al-Numan, recaptured by Syrian government forces, the army said on Wednesday. AFP / STAFF

Turkish President Recep Tayyip Erdogan accused Moscow on Wednesday of "not honouring these agreements".

It was a rare critical remark from Erdogan, who has largely sought to keep good relations with Russian President Vladimir Putin since a 2016 rapprochement.

Displaced Syrians drive through Hazano in the northern countryside of Idlib after fleeing its southern countryside towards areas further north near the border with Turkey, as a result of an ongoing offensive by regime forces on Syria's rebel-held northwes
Displaced Syrians drive through Hazano in the northern countryside of Idlib after fleeing its southern countryside towards areas further north near the border with Turkey, as a result of an ongoing offensive by regime forces on Syria's rebel-held northwestern region. AFPTV / Omar HAJ KADOUR

Tens of thousands of civilians have fled the government's advance on the south of the province in recent weeks, seeking safety closer to the Turkish border further north.

The violence in the northwest has displaced more than 388,000 civilians since December, the United Nations says.

At least 20,000 of them have moved in the last two days, said UN undersecretary general for humanitarian affairs Mark Lowcock on Wednesday.

"Unless the current hostilities stop, we will see an even greater humanitarian catastrophe," he told the UN Security Council.

The exodus of civilians fleeing the government's advance has caused traffic jams in Syrian towns closer to the Turkish border
The exodus of civilians fleeing the government's advance has caused traffic jams in Syrian towns closer to the Turkish border AFP / Omar HAJ KADOUR

In areas north of Maaret al-Numan, bombardment by government ally Russia has prompted a fresh wave of displacement in recent days, with hundreds of vehicles cramming a key exit route, AFP correspondents reported.

Aid groups have warned the latest violence is compounding one of the worst humanitarian disasters of the nine-year war.

Government forces, which now control around 70 percent of Syria, have repeatedly vowed to retake the entire country, including Idlib.

After Maaret al-Numan's recapture, the Syrian army was bent on continuing the fight "until all Syrian soil has been cleansed of terrorism", it said in a statement.

On Wednesday, loyalist forces swept the town for booby traps and unexploded ordnance after all rebels were either killed or withdrew, the Britain-based Observatory said.

The town was once a defiant hotspot for anti-Assad protests, drawing in crowds from surrounding villages, but today its streets are largely empty.

It is home to a museum of Roman and Byzantine-era mosaics, which volunteers sought to protect with sandbags through years of war.

What remains of rebel-held territory includes more than half of Idlib province, as well as slivers of adjacent Aleppo and Latakia.

Government forces and rebels were locked in clashes in the south of Aleppo province on Wednesday, the Observatory said.

State news agency SANA said government forces on Wednesday gained ground against rebels and jihadists in the Rashideen area in the province's west.

To the north of Maaret al-Numan, the front line had been pushed back to within 10 kilometres (six miles) of Saraqeb, the next town on the M5 highway, Observatory director Rami Abdel Rahman said.

Russia's RT television network said Wednesday that one of its correspondents was seriously wounded by shellfire whilst reporting on Maaret al-Numan's capture.

Government forces have recaptured around 27 towns and villages from their rivals in southern Idlib since January 24.

The civil war has killed more than 380,000 people and displaced more than half the country's population since it erupted following the brutal repression of anti-government protests in 2011.

Several UN-backed rounds of peace talks have failed to stem the bloodshed and a parallel track led by regime backer Russia and rebel ally Turkey has gained precedence in recent years.

On Wednesday, UN envoy Geir Pedersen visited the foreign ministry in Damascus, where he met with Syrian foreign minister Walid Muallem.

A long-awaited committee to draw up a post-war constitution for Syria met in October in Geneva, but Pedersen has acknowledged it made little progress.