Syria's stolen antiquities After Assad, a gold rush for looters and grave robbers

They come by night. Armed with pickaxes, shovels and jackhammers, looters disturb the dead.

- William Christou

Men exhume graves dug more than 2,000 years ago in Syria's ancient city of Palmyra, searching for treasure.

By day, the destruction caused is apparent. Three-metre-deep holes mar the landscape, where ancient burial crypts lure people with the promise of artefacts that fetch thousands of dollars.

Mohammed al-Fares, a resident of Palmyra and an activist with the NGO Heritage for Peace, said: "These different layers are important. When people mix them together, it will be impossible for archaeologists to understand what they're looking at." He picked up a shattered piece of pottery and placed it next to the rusted tailfin of a mortar bomb. Palmyra, which dates back to the third century BC, suffered heavy damage under Islamic State control, when militants blew up parts of the ancient site in 2015, deeming its ruins apostate idols.

Experts say the looting and trafficking of Syria's antiquities has surged to unprecedented levels since rebels overthrew Bashar al-Assad in December.