Speaking in Syria’s southern neighbour Jordan after talks with Foreign Minister Ayman Safadi, Mr Lavrov said that Riyadh supported the “de-escalation zones” agreed at a series of peace talks in Kazakhstan’s capital Astana.

He told reporters: “I think Saudi Arabia is determined to solve the Syria crisis.”

The truce zones in the densely populated west of Syria are guaranteed by Syria’s allies Russia and Iran, as well as Turkey, which has backed Syrian insurgents.