Rebel forces in Syria say they have entered Syria’s second-largest city, Aleppo, in the biggest offensive against the government in years.

Video posted on a channel linked to the rebels appears to show their fighters in vehicles inside the city. The footage was geolocated by the BBC in a western suburb of Aleppo.

A British-based group said militants detonated two car bombs before advancing into the city’s neighborhoods on Friday.

Government troops, meanwhile, say they have recaptured positions in several cities in Aleppo and Idlib provinces following an offensive by the militant Islamist group Hayat Tahrir al-Sham (HTS) and allied factions on Wednesday.

A statement released on the rebel-affiliated channel on Friday said: “Our forces have begun to enter the city of Aleppo.”

Earlier, the Syrian Observatory for Human Rights (SOHR) monitoring group, which uses a network of sources on the ground in Syria, reported that Syrian and Russian aircraft carried out 23 airstrikes on the Aleppo region on Friday.

SOHR said 255 people, mostly combatants, were killed in the fighting, the deadliest between rebels and pro-government forces in Syria in years.

Opposition forces have taken control of more than 50 towns and villages since Wednesday, it said.

Fighting that had raged since Syria’s civil war began in 2011 had largely subsided in 2020 when Turkey and Russia – Syria’s main ally – negotiated a ceasefire to stop a government push to retake Idlib.

This led to a prolonged lull in violence, but sporadic clashes, airstrikes and shelling continued.

Idlib is the last remaining opposition stronghold and home to more than four million people, many of whom were displaced during the conflict and live in terrible conditions.