The official, who was speaking on condition of anonymity, said supplies of modern, high-powered weaponry including guided anti-tank weapons would be increased to the Arab-and Western-backed rebel groups fighting the forces of Syria's President Bashar Assad, the BBC reported on Friday.

He did not rule out supplying surface-to-air missiles to the rebels, a move resisted by many in the West for fear that they would fall into the hands of ISIL and end up being used to shoot down warplanes of the US-led coalition or even civilian airliners.

He said the weapons would go to three rebel alliances — Jaish al-Fatah (Army of Conquest), the so-caled Free Syrian Army (FSA) and the Southern Front.

On October 2 the United States and its allies — Britain, France, Germany, Turkey, Qatar and Saudi Arabia — urged Russia to end its airstrikes against the forces of the so-called “moderate opposition” in Syria, warning this would further escalate the conflict and lead to a new weave of extremism and radicalism in the war-torn country.

Russia insists its aerial campaign in Syria exclusively targets the forces of the ISIS terrorist group.

In Russia, Kremlin spokesman Dmitry Peskov said Friday Russia's airstrikes against terrorist groups in Syria will continue while Syria's government-led army carries out its ground offensive, Spuntik News reports.