A decades-long backer of the Damascus regime, Moscow has remained a steadfast supporter of President Bashar al-Assad throughout four and a half years of war that have left more than 240,000 people dead.

Its recent deployment of its own troops and warplanes to Syria, combined with new arms deliveries to Assad’s armed forces, appear to have prompted a significant shift in international efforts to end the conflict.

On Monday, Russian President Vladimir Putin will meet his US counterpart President Barack Obama on the sidelines of the UN General Assembly meeting in New York.

Saturday was the 15th straight day that Russian transport aircraft had flown in troops and equipment to the Hmeimim base in Latakia province on the Mediterranean coast, a military source told AFP on condition of anonymity.