UN Security Council members are seeking "clarity" on opposition claims that Syrian troops used chemical weapons in an attack near Damascus, Argentina’s UN envoy, the council president, said Wednesday.

UN Security Council members are seeking "clarity" on opposition claims that Syrian troops used chemical weapons in an attack near Damascus, Argentina's UN envoy, the council president, said Wednesday.

"There must be clarity on what happened and the situation must be followed carefully," Argentina's envoy Maria Cristina Perceval said after the council met behind closed doors.

Council members -- who were briefed by Deputy Secretary General Jan Eliasson -- "welcomed the determination of the secretary general to ensure a thorough, impartial and prompt investigation," she said.

There was a "strong call for a cessation of hostilities and for a ceasefire," she said.