At least 21 people, including children, suffered breathing difficulties Monday (January 22nd) in a suspected Syrian regime chemical attack on a besieged opposition enclave near Damascus, AFP reported.

UN inspectors have accused the Syrian regime of being behind multiple deadly poison gas attacks during the country's seven year war.

Monday's attack targeted the city of Douma in the opposition-held region of Eastern Ghouta, the Syrian Observatory for Human Rights said.

"After regime forces fired rockets into the western part of the city of Douma, white smoke spread, causing 21 cases of suffocation," it said.

A doctor at a hospital in the city who gave his first name as Bassil said patients were suffering "respiratory irritation, breathing difficulties, coughing and reddening of the eyes".

"We noticed that they smelled like bleach, or chlorine, and we stripped them of their clothes," he said.

Six children and six women were among those affected, the Observatory said.

"Residents and medical sources talk of chlorine gas," Observatory hear Rami Abdel Rahman said, adding that the Observatory could not confirm those reports.