France has called on the UN Security Council to issue a resolution to punish those responsible for the use of chemical weapons in Syria.
Human Rights Watch said in a report on Monday that the Syrian regime's forces used chemical weapons in opposition-held areas in Aleppo during fighting to regain control of the city late last year.
The human rights organisation said its report was based on interviews with witnesses, analysis of videos and photos and social media posts. "Assad regime helicopters dropped chlorine bombs in residential areas in Aleppo on at least eight occasions between November 17 and December 13, 2016," it said.
The report adds to the growing evidence of the Syrian regime's use of prohibited chemical weapons.
Britain, France and the United States have increased calls to impose sanctions on Syrian officials.