Two rebel groups are leading the push. One is Hayat Tahrir al-Sham ( HTS ), which emerged from al-Qaeda’s Syrian affiliate. It cut ties with the jihadist group in 2017 and has since set up a provisional government in rebel-held Idlib province in north-west Syria. The other faction, the Syrian National Army ( SNA ), is a Turkish proxy.

The rebel coalition consists of "well-established armed Islamist factions who, despite their differences, are united in fighting Assad and Iran-backed militias", said CNN. But the driving force behind the fighting is Hayat Tahrir al-Sham (HTS), a "formidable" and controversial faction with deep roots in Syria's ongoing civil war.