Video images of what is said to be another chlorine gas attack by government forces in Syria have been posted online by an opposition group.
The BBC reports the images, which cannot be verified, show medics trying to revive four young men. A voice off-screen said the location is Harasta, just outside the capital Damascus.
It is the fourth chemical weapons attack alleged by the opposition this month.
Use of chlorine as a weapon of war is banned. Western countries earlier threatened military strikes until Syria agreed to declare its stockpiles of chemical weapons and hand them over to the Organisation for the Prohibition of Chemical Weapons for destruction.
The BBC reports the chemicals are supposed to be completely destroyed by 30 June but the OPCW recently warned that the deadline will be missed unless Syria significantly speeds up delivery.
Syria's 13th consignment of chemicals was shipped out of Latakia port on Monday, taking the amount removed so far to 65% of declared stockpiles