Russian President Vladimir Putin (R) shakes hands with Turkish President Recep Tayyip Erdogan after their joint press conference following the talks, in the Bocharov Ruchei residence in the Black Sea resort of Sochi on Sept. 17, 2018. (Xinhua/AFP)

UNITED NATIONS, Sept. 18 (Xinhua) -- UN Special Envoy on Syria Staffan de Mistura on Tuesday asked for the quick implementation of a Russia-Turkey agreement to set up a demilitarized buffer zone in Syria's Idlib province, which could avert a full-scale attack on the last major rebel stronghold in the country.

"We hope that this agreement is expeditiously implemented, with full respect for international humanitarian law; with sustained humanitarian access; with respect for the sovereignty, independence, unity and territorial integrity of Syria; and with continued preference for dialogue over escalation in addressing a complex situation," de Mistura told the Security Council in a briefing.

Russian President Vladimir Putin and Turkish President Recep Tayyip Erdogan agreed on Monday to establish a demilitarized zone within Idlib.

The Syrian government has welcomed the agreement and confirmed its full coordination with Russia, said de Mistura.

"I welcome the fact that diplomacy has produced progress in the effort to address the challenges posed by UN Security Council-listed terrorist groups while protecting civilians -- up to 3 million of them, including a million children. I thank Presidents Putin and Erdogan for their personal engagement. I also believe that the strong international engagement on the dangers of a full-scale offensive in Idlib has been important," said de Mistura.

He reported negative developments in other areas of Syria.

This week fresh airstrikes were reported in the capital city of Damascus, which the Syrian government attributes to Israel. Israel has not commented, he said.

Late Monday, a Russian military aircraft was downed, killing 15 servicemen. The Russian Defense Ministry has stated that the plane was accidentally downed by Syrian government anti-aircraft fire, which was responding to Israeli fighter jets carrying out attacks just off the coast, he said.

Russia has blamed Israel for a provocation. Israel has stated that Israeli jets were targeting weapons shipments headed for Lebanon that threatened Israeli security, and has blamed the Syrian government for the incident, said de Mistura.

"We call upon all parties to refrain from military actions that would only exacerbate a complex situation," he said.

Despite the bad news, he asked for efforts to carry forward the political process in Syria since a full-scale attack on Idlib seems to have been averted.

"But for now, we are pleased that there is de-escalation in one major area: Idlib. And now that we have this deal, there is no reason not to move forward expeditiously with the political process," he told the Security Council.

Syrians look to the United Nations to facilitate a political process that can help them exit this war and enter into a better future -- a future that they determine, independently and democratically. That requires a real dialogue and genuine negotiation -- a process that is credible and inclusive, he said.

There is no military solution -- in Idlb, or anywhere else, he said. "We need an inclusive political process, and the UN is here to facilitate that process, starting with a constitutional committee getting to work."