“The chances of success will be greater if the parties here are able to agree on a mechanism to oversee and implement nationwide ceasefire. A mechanism to oversee and implement a nationwide ceasefire,” said Staffan de Mistura. “We didn't have it in the past, that's the reason why often we failed.”

He encouraged the guarantors of the ceasefire to create a mechanism to implement the consolidation and de-confliction ceasefire measures, and “to see what else can be done to build confidence.”

Sitting alongside representatives of the Government of Syria and the Syrian opposition, de Mistura reiterated that the only way to end the conflict and secure a political solution is through negotiation among the Syrians.

The closed-door meeting – convened by Iran, Russia and Turkey, with a representative from the United States attending as an observer – is meant to end tomorrow.

The Special Envoy said that he hoped by strengthening the ceasefire at the Astana meeting “we could see in Geneva genuine intra-Syrian negotiations,” referring to the 8 February negotiations to be held under the auspices of the UN.

“I would hope direct negotiations between empowered and inclusive delegations of the Government and the opposition to take place,” de Mistura said, which include issues of “governance, constitution , elections” in the context of Security Council resolution 2254 (2015).

He praised the parties for the ceasefire announced by President Vladimir Putin and President Recep Tayyip Erdoğan, with support of Iran, in December for saving lives, and encouraged others to join.

“All other armed opposition groups not affiliated to terror organisations designated as such by the Security Council, in addition to groups allied with the Government, should also listen to the call to abide by the ceasefire,” de Mistura said.

Protection of civilians must be a crucial priority, he underscored, calling for the protection of civilian infrastructure, including hospitals, schools, water and electricity networks, and areas such as markets.