Syrian armed group Hayat Tahrir al-Sham (HTS) launched an attack on regime forces in the last opposition enclave in northern Syria on Wednesday, seizing territory in the first such advance in years, army and rebel sources said.
The offensive over-ran at least 10 areas under the control of Syrian President Bashar al-Assad in northwestern Aleppo province, said a source in the operations room run by a coalition of insurgent groups led by HTS.
HTS, which is led by Al-Qaeda's former Syria branch, killed 31 members of the regime forces and 26 members of their own during clashes that ensued after the raid, according to Britain-based war monitor, the Syrian Observatory for Human Rights (SOHR).
HTS is as a designated terrorist organisation by the United States that has long been targeted by Syrian-government and Russian forces.
The land incursion is the first such territorial advance since March 2020 when Russia, which backs Assad, and Turkey, which supports the rebels, agreed to a ceasefire that led to military action halting in Syria's last major rebel stronghold in the country's northwest.
The group advanced almost 10 km from the outskirts of Aleppo city and a few kilometres away from Nubl and Zahra, two Shia towns where Lebanon's Hezbollah has a strong presence, an army source said.
They attacked Al-Nayrab airport east of Aleppo.
The group says the campaign was in response to stepped-up strikes in recent weeks against civilians by the Russian and Syrian air force on areas in southern Idlib, and to pre-empt any attacks by the Syrian army, which was building up troops near front lines with rebels.
The army pounded areas near rebel-held Idlib city and the cities of Ariha and Sarmada along with other areas in southern Idlib province, according to an army source.
Official media did not report the fighting but pro-government websites said the army had pounded HTS hideouts and killed dozens.
Witnesses said hundreds of families in the last refuge for opponents of Assad fled to safer areas along the Turkish border.
It competes with Turkey-backed mainstream rebels groups that also control swathes of territory along the border with Turkey in northwest Syria.