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. Maaret al-Numan, a former anti-government protest hotspot turned ghost town after weeks of bombardment, lies on a key highway connecting the capital Damascus to second city Aleppo.

The M5 artery has long been in the sights of the government as it seeks to revive a moribund economy ravaged by almost nine years of war. "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.

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

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. 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.

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.