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
The British and American flags were lowered and folded up for the final time at Camp Bastion in Afghanistan.
The secret wartime bunker of fascist leader Benito Mussolini opens its door to public.
As the main British base in Afghanistan, Camp Bastion, is handed over to Afghan troops we look back at Britain's role in the conflict.