Syria is using currency printed in Russia to pay its soaring deficit, Suleiman Al-Khalidi of Reuters reports.

Four Damascus-based bankers told Reuters that the new cash has entered circulation because international sanctions have derailed oil exports and other government revenues.

Consequently, the central bank has exceeded borrowing limits from public banks while private banks are reluctant to buy government bonds.

The government's biggest priority is paying the salaries of over 2 million state employees (among a workforce of 4.5 million in a country of more than 21 million) so that the public sector doesn't collapse.

One banker told Reuters this was a "last resort."

Russia is also sending attack helicopters to Syria.