Volunteer emergency workers say people suffered breathing difficulties after an attack on the Sukari area.

The reports could not be independently verified. AUN-led investigation in August found the government had used chlorine on at least two occasions.

The Syrian government has always denied using chemical weapons.

Ibrahem Alhaj, a Syrian Civil Defence rescue worker, said he had reached the scene of the attack shortly after a helicopter dropped barrels containing what he said were four chlorine cylinders.

Syrian Civil Defence, a volunteer emergency response team that operates in opposition-held areas, posted video on its Facebook page showing distressed children using oxygen masks to breathe.

(BBC News)