Qusayr, a once bustling commercial hub in western Syria, has not seen any fighting since government troops, with the help of Lebanon's powerful Iran-backed Hezbollah group, drove out Sunni Muslim rebels six years ago.

Large sections of the city lie in ruin and of the thousands who fled the violence, most have not returned. Only about 10,000 people — a tenth of its prewar population — have come back.

According to former residents living abroad, this is partly because Qusayr, around 10 km (6 miles) from the Lebanese border, is now a security zone where only those with special permission can enter.