Following Russia and the United States agreement on the text, the U.N. security council unanimously approves an international roadmap for a peace process in Syria. The resolution does not touch on the question of Bashar al-Assad's fate.
Organization for the Prohibition of Chemical Weapons inspectors conclusively identify mustard gas as the toxic agent used in the battle between Islamic State (IS) insurgents and an anti-Assad rebel group in the Syrian town of Mare' in the northern Alleppo province on August 21, 2015. This is the first confirmation of its use by non-state actors in Syria’s four-year-old conflict.
The U.N team in charge of the investigation on the alleged recent chemical attacks in Syria comes under fire from snipers; none of the U.N. delegates are injured and the team reaches one of the alleged hit sites. The U.S. Secretary of State John Kerry describes the attack as "a shame and an offense to the world and humanity that deserves the proper punishment".