The fact-finding mission from the Organisation for the Prohibition of Chemical Weapons (OPCW) is investigating reports that government forces launched an April 7 chemical attack in the final stages of their fight to retake the town of Douma from rebels.
Vassily Nebenzia, Russia's ambassador to the United Nations, said the idea of establishing a mechanism to determine responsibility for the use of chemical weapons is "futile" since Washington and its allies already identified who the "culprits" are, referencing the US-led attack on Syria.
Asked about the draft text, Russian Ambassador Vassily Nebenzia told AFP that it was "untimely", indicating Moscow was not ready to engage with the West on Syria after the military strikes.
The US and France say they have evidence that Mr Assad's forces used poison gas in the attack, but they have not provided any evidence, even after Saturday's missile strikes.
The U.S., United Kingdom and France accuse President Bashar Al-Assad of carrying out the April 7 attack, which killed dozens of people.
Syrian state media reported that missiles had again targeted an airbase overnight, but the commander in the regional military alliance backing the government, speaking on condition of anonymity, later told Reuters it was a false alarm. Yarmouk, Syria's biggest camp for Palestinian refugees, has been under the control of Islamic State fighters for years.
"The two leaders emphasized the importance of continuing the joint efforts of Turkey, Iran and Russia.to protect Syrian territorial integrity and find a lasting, peaceful solution to the crisis", a Turkish presidential source said following telephone talks between President Recep Tayyip Erdoğan and Iranian counterpart Hassan Rouhani.
Opposition forces say Dumair airport had been used in the military campaign to regain eastern Ghouta, a rebel enclave on the outskirts of Damascus. Russian Federation and Iran, both allies of Syrian President Bashar al-Assad, have condemned the strikes - and Moscow has suggested the attack was "staged".