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

Video posted on a channel affiliated with the Islamist militant group Hayat Tahrir al-Sham (HTS) appears to show their fighters in vehicles inside the city. BBC Verify has geolocated the footage to a western suburb of the city.

This is the first time rebels fighting the forces of President Bashar al-Assad have reached Aleppo since being forced out by the army in 2016.

Government forces meanwhile say they have regained positions in a number of towns in Aleppo and Idlib provinces, following an offensive launched by HTS and allied factions on Wednesday.

More than half a million people have been killed in the civil war that erupted after the government cracked down on pro-democracy protests in 2011.

An array of armed groups opposed to the Assad government – including jihadists – took advantage of the turmoil to seize swathes of territory.

The Syrian government – with help from Russia and other allies – later retook most the areas it had lost.

Idlib, the last remaining opposition stronghold, is mostly controlled by HTS, but Turkish-backed rebel factions and Turkish forces are also based there.

On Friday a statement posted on the rebel-affiliated channel said: “Our forces have begun entering the city of Aleppo.”

Videos verified by the BBC show armed men running in a street about seven kilometres (4.3 miles) from Aleppo’s medieval citadel in the centre of the city.

Another clip verified by the BBC showed large groups of people carrying luggage walking away from an area near Aleppo University. That video was recorded 3km away from a location where HTS-affiliated media claim rebel forces have entered the city.

The government says reinforcements have now reached Aleppo and it is driving the rebels out.

The UK-based monitoring group Syrian Observatory for Human Rights (SOHR), which uses a network of sources on the ground in Syria, reported that Syrian and Russian planes carried out 23 air strikes on the Aleppo region on Friday.

The SOHR said 255 people had been killed in the fighting, the deadliest between rebels and pro-government forces in Syria for years.

Fighting in Idlib had largely wound down since 2020, when Turkey and Russia, Syria’s key ally, brokered a ceasefire to halt a push by the government to retake the province.

But on Wednesday HTS and its allies said they had launched their offensive to “deter aggression”, accusing the government and allied militias of escalation in the region.

It came as the Syrian government and its allies were preoccupied with other conflicts.

In neighbouring Lebanon, an Israeli military campaign has devastated the Iran-backed Hezbollah movement, whose fighters helped turned the tide of the Syrian civil war.

Israel has also stepped up its air strikes inside Syria on targets linked to Iran and Iran-backed groups.

Additional reporting by Lina Sinjab in Beirut and Richard Irvine-Brown, Merlyn Thomas and Paul Brown in London.