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.

Mr. al-Assad’s international backers, including Russia, Iran and the Lebanese militia Hezbollah, are weakened and distracted by wars in Ukraine, Gaza and Lebanon, making it an opportune moment for the Syrian rebels to attack.

Syria’s devastating civil war, responsible for more than 300,000 deaths, was never officially resolved. Lightning gains by rebels opposed to President Bashar al-Assad were opportunistic, but also indicated years of patient preparations.

Opposition supporters are ecstatic but others are wary of their new Islamist rulers as Assad regime begins counteroffensive

A historian explains why U.S. sanctions and Iran and Russia’s entanglements in other wars helped create an opening for rebel groups to overrun the Syrian Army.

Images shared on social media have illustrated the anger that Syrian rebels fighting President Bashar al-Assad feel toward his ally Vladimir Putin. The Russian leader has been indispensable in propping up Assad's regime during the brutal Syrian civil war that started in 2011 but has been essentially frozen over the last four years.

Airstrikes also hit residential buildings in the city of Idlib, which has become a refuge for people displaced by the civil war, killing at least 12 civilians, according to the White Helmets, an independent rescue organization.