Local activists said Isis had imposed a curfew and was sweeping the city for remnants of Assad’s forces. Isis has also massacred members of the Shaitat tribe, which fought alongside the Assad regime in Palmyra and had railed against Isis in Deir Ezzor – a rebellion in which the militant group killed 800 members of the tribe.

Control of Palmyra leaves Isis with unopposed access to the city’s magnificent ruins, amid fears that they will destroy significant chunks of Syria’s heritage as they did in Iraq.

But more significantly, Isis controls vast swaths of Syria, from Palmyra to Raqqa and Deir Ezzor in the country’s west, a tract that the Syrian Observatory for Human Rights estimates to be 95,000 sq km, or more than half Syria’s landmass. With its seizure of the Arak and al-Hail gas fields near Palmyra, it also controls much of the country’s electricity supply – those two fields power much of the Syrian regime’s strongholds in the west.