"The Union of Medical Care and Relief Organizations (UOSSM) also concluded that the symptoms of the casualties were consistent with exposure to a nerve agent, possibly one mixed with chlorine. Dr Raphal Pitti of UOSSM France said he thought "chlorine was used to conceal the use of [the nerve agent] Sarin".

The United States, which supports the opposition to Mr Assad, said the victims' symptoms appeared to be "consistent with an asphyxiation agent and of a nerve agent of some type"

"At 19:45, more than 500 patients - most of them women and children - were brought to medical facilities with symptoms indicative of exposure to a chemical agent, according to the Syria Civil Defence and the Syrian American Medical Society (SAMS), a relief organisation that supports hospitals.

The patients showed signs of "respiratory distress, central cyanosis (blue skin or lips), excessive oral foaming, corneal burns, and the emission of chlorine-like odour", a joint statement issued on Sunday said. One woman who died had convulsions and pinpoint pupils"

BBC