What is happening in north-western Syria and why now?

For several years, Idlib remained a battleground as Syrian government forces tried to regain control.

But in 2020, Turkey and Russia brokered a ceasefire to halt a push by the government to retake Idlib. The ceasefire largely held despite sporadic fighting.

In October, the UN special envoy for Syria said HTS had carried out a significant raid into government-held areas, Russia had resumed air strikes for the first time in months, and pro-government forces had significantly accelerated drone strikes and shelling.

On Wednesday, HTS and allied groups said they had launched an offensive to “deter aggression”, accusing the government and allied Iran-backed militias of escalation in the north-west.

But it came at a time when the Syrian government and its allies were preoccupied with other conflicts.

The Iran-backed Lebanese group Hezbollah, which was crucial in helping Assad push back rebels in the early years of the war, has suffered recently from Israel’s offensive in Lebanon, while Israeli strikes have eliminated Iranian military commanders in Syria and degraded supply lines to pro-government militias there. Russia is also distracted by the war in Ukraine.

Without them, Assad’s forces have been left exposed.