A chemical attack on a rebel-held town in eastern Ghouta has killed dozens of people, medical services reported, and Washington said the reports - if confirmed - would demand an immediate international response.
A joint statement by the medical relief organisation Syrian American Medical Society (SAMS) and the civil defence service, which operates in rebel-held areas, said 49 people had died in the attack late on Saturday. Others put the toll at 150 or more.
The Russian-backed Syrian state denied government forces had launched any chemical attack as the reports began circulating and said the rebels were collapsing and fabricating news.Reuters could not independently verify the reports.