The US State Department has reported indications that a toxic industrial chemical, probably chlorine, was used in the Syrian town of Kfar Zeita this month.
"We have indications of the use of a toxic industrial chemical" US spokeswoman Jen Psaki said, referring to the rebel-held area in the central province of Hama.
Psaki said the United States was still trying to determine the facts and that "there needs to be an investigation of what's happened here."
More top news
Scientists have discovered the world's deepest fish with wing-like fins and an eel-like tail during research in the depths of the Pacific.
The tranquil district of Hart has been crowned as the place with the best quality of life in the UK for the fourth year in a row.
Britain's immigration system is in 'critical condition' according to the chair of the Home Affairs Select Committee.