A Syrian human rights group is accusing President Bashar al-Assad's government of carrying out fresh attacks using toxic chlorine gas.
The Syrian Network for Human Rights said one person was killed and over 60 were wounded Thursday when government helicopters dropped gas-filled barrel bombs on at least three locations.
The rights group said via Twitter the attacks took place in three villages in northwest Syria: al-Janoudiyah, Kansafra and Hizareen, where the bombs hit a hospital.
President Assad has repeatedly been accused of using chemical weapons on civilians and fighters attempting to overthrow his government.
Following a particularly gruesome sarin gas attack on a rebel-held area in late 2013, Assad agreed to dismantle his chemical weapons facilities and destroy the stockpiles.
But chlorine was not included as part of the chemical weapons to be dismantled, since it also has civilian uses.
President Assad has strongly denied using chemical weapons, instead blaming any such attacks on rebels. Rights groups, however, continue to insist Damascus has not stopped using toxic agents as weapons.
Human Rights Watch said last month evidence "strongly suggests" Damascus used toxic chemicals, suspected to be chlorine, in several deadly barrel bomb attacks in Idlib province in March.
The Organization for the Prohibition of Chemical Weapons, which helped dismantle Syria's chemical weapons, is attempting to carry out a fact-finding mission on those attacks and others, but it does not have the mandate to assign blame.
The U.S. has been pushing for the U.N. Security Council to find ways to hold Syria accountable for the suspected chlorine attacks. Diplomats said Thursday that one such way would be to create a team of U.N. investigators who would identify who used the weapons.
The plan is likely to face opposition from Russia, Syria's main ally, which has vetoed several Security Council resolutions critical of President Assad's government.