Russia has retained its historical role as the key weapons supplier to Bashar al-Assad's regime over the past 18 months. It is believed to have sent at least three shipments of heavy ammunition to the jointly run port of Tartous in northern Syria. Other Russian supplies are thought to have been flown in.
In late September, Russian envoys around the world were summoned to Moscow for an annual gathering. One ambassador present said the unexpected presence of Soviet hardliners, including Yevgeny Primakov, meant no imminent change in Russia's support, or let-up in weapons supplies.
Moscow has refurbished Syrian attack helicopters, but has been unable to deliver some of them after interference from western Europe.