Syrian rebels launched a large-scale military operation on Wednesday against Syrian government forces in the last remaining opposition-held enclave in northern Syria. This marks the first significant territorial advance by the rebels in several years, according to both army and rebel sources.

The rebel offensive, which targeted northwestern Aleppo province, led to the capture of at least 10 areas previously under the control of Syrian President Bashar al-Assad’s forces. The operation was led by a coalition of insurgent groups, including the militant group Hayat Tahrir al-Sham, which runs an operations room for the offensive.

This territorial gain is the first since March 2020, when Russia, a key backer of the Assad regime and Turkey, which supports the rebels, brokered a ceasefire that halted military action in Syria’s last major rebel stronghold. Rebel forces advanced nearly 10 kilometres (6 miles) from the outskirts of Aleppo city, moving closer to the Shi'ite towns of Nubl and Zahra, which have a significant presence of Hezbollah fighters backed by Iran. The rebels also attacked Al-Nayrab airport, located east of Aleppo, where pro-Iranian militias maintain outposts.

Rebel leaders say the offensive was a direct response to a recent uptick in airstrikes by the Russian and Syrian air forces on civilian areas in southern Idlib. They also cited the Syrian army’s troop buildup near the front lines with rebels as a preemptive measure to thwart any potential Syrian military assault.

In retaliation, the Syrian army carried out airstrikes on rebel-held areas near Idlib city, as well as in the towns of Ariha and Sarmada, located in southern Idlib province. While official Syrian media has yet to report the fighting, pro-government websites claimed that the army had targeted Hayat Tahrir al-Sham hideouts, resulting in the deaths of dozens.

Witnesses reported that hundreds of families fled the violence in Idlib, seeking safety near the Turkish border, which marks the last refuge for opposition supporters of Assad. Hayat Tahrir al-Sham, a group designated as a terrorist organisation by the United States, has long been targeted by the Syrian government and Russian forces. The group competes with Turkey-backed mainstream rebel factions, which also control large areas along Syria’s border with Turkey in the northwest.