The main Western-backed Syrian opposition group has called on the United Nations to send a fact-finding mission to investigate an alleged poison gas attack on a rebel-held town.
The Syrian National Coalition and activists inside Syria say the government carried out a chlorine gas attack on the town of Sarmin in northwestern Syria late Monday, killing six people and leaving dozens more struggling to breathe. Syrian authorities denied the allegations.
In a statement released late Tuesday, Coalition vice president Hisham Marwa called for an on-site UN investigation as soon as possible. He also demanded the Security Council enforce a recent resolution that condemns the use of toxic chemicals such as chlorine in Syria and threatens military action in case of violations.
"The UN Security Council must take all necessary measures that ensure the enforcement of the resolution," Marwa said.
The spokesman for the Organization for the Prohibition of Chemical Weapons, Peter Sawczak, said Wednesday the watchdog agency views "any allegations of chemical weapons use with concern and we are monitoring the situation closely."
Amateur videos posted online purported to show the aftermath of the Sarmin attack. In one video, medics tried to resuscitate three children, including one dazed child whose head lolled slowly to the side. The video appeared genuine and corresponded to other Associated Press reporting.
Monday's purported attack would be one of the most serious uses of poison gas in Syria since a deadly chemical attack outside Damascus in August 2013.
An OPCW fact-finding mission concluded "with a high degree of confidence" that chlorine was used on three rebel-held villages in Syria last year, killing 13 people. It did not assign blame. Last month, the OPCW condemned the use of chlorine in Syria as a breach of international law.
Despite the new Security Council resolution, an international consensus on who was responsible for a violation would be needed to take any action, which would likely prove difficult. The Security Council remains divided over Syria's civil war, with the U.S. and its allies supporting the opposition, and Russia backing Syrian President Bashar Assad.