Syrian and allied forces backed by Russian airstrikes drove Islamic State militants out of the town of al-Qaryatain on Sunday after encircling it over the past few days, Syria's military command said.

Surrounded by hills, al-Qaryatain is 100 km (60 miles) west of the ancient city of Palmyra, which government forces recaptured from Islamic State last Sunday.

Al-Qaryatain had been held by the militant group since late August. Syrian President Bashar Assad has been trying to retake al-Qaryatain and other pockets of Islamic State control to reduce the jihadi group's ability to project military power into the heavily populated western region of Syria, where Damascus and other main cities are located.