Syria's stocks of a key chemical used to produce the deadly nerve agent sarin have been destroyed, the mission overseeing the destruction of its chemical arsenal said. The Organisation for the Prohibition of Chemical Weapons-UN "joint mission confirms the destruction of the entire declared Syrian stockpile of isopropanol", a statement said late on Tuesday. "Now 7.2 percent of Syria's chemical weapons material remains in country and awaits swift removal for onward destruction. The joint mission urges the Syrian authorities to undertake this task as soon as possible," the statement added. Under a US-Russian deal negotiated last year, Syria signed up to the Chemical Weapons Convention and agreed to hand over its entire chemical weapons arsenal by June 30 of this year. The deal came after a sarin attack in August killed some 1,400 people in an opposition-held area near Damascus. While the opposition and its Western backers blamed forces loyal to President Bashar al-Assad, his government and its Russian ally blamed the rebels. The agreement headed off a US threat of military action. Assad's regime now faces new Western allegations that it unleashed the industrial chemical chlorine on a rebel-held village in central Hama province last month. Syria was not required to declare its stockpile of chlorine -- a toxic but weak agent -- as it is widely used for commercial and domestic purposes. But its use for military purposes would be a breach of the Chemical Weapons Convention and the OPCW announced a fact-finding mission last month.