A leading human rights group says it has strong evidence that Syria's army used chemical weapons on rebel-held areas last month.
Human Rights Watch said on Tuesday that forces loyal to President Bashar al-Assad likely used chlorine gas on three towns in northern Syria in mid-April.
The New-York based group said chlorine canisters appear to have been embedded into crude explosive-laden barrels and dropped on rebel-held areas by military helicopters, according to interviews with witnesses, video footage and photographs.
The claim adds to growing concerns that Syria's government is still using chemical weapons, months after a chemical attack killed hundreds of civilians last August.
In late April, the UN's chemical watchdog said it would investigate the chlorine claims.
