UNITED NATIONS, September 18. /TASS/. The United Nations welcomes the agreements reached by Russian and Turkish Presidents, Vladimir Putin and Recep Tayyip Erdogan, on the situation in Syria’s Idlib, United Nations Secretary General’s Special Envoy for Syria Staffan de Mistura said on Tuesday.

"We 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," he said. "I thank Presidents Putin and Erdogan for their personal engagement."

The United Nations has warned against any actions that might deteriorate the situation in Syria following yesterday’s incident with a Russian plane that was downed in that country, killing 15 servicemen.

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

The agreements concerning the establishment of a Syrian constitutional committee should be implemented in October, he said. 

"It is too easy to say: we will keep consulting; if we are not careful this becomes an end in itself," he said. "I believe the time is approaching for me to indicate a fixed date by which the Sochi Final Statement is given effect to by launching the constitutional committee. This next month is therefore critical. I am ready to engage all. In addition to the international players, I look forward of course to engaging the Syrian parties, starting with the Syrian government, since their active involvement is obviously crucial if a constitutional committee is to proceed," the UN envoy added.

Participants in the Syrian National Dialogue Congress, held in the Russian Black Sea resort of Sochi on January 30, decided to establish a constitutional committee that will work on the country’s new constitution together with de Mistura.