Syria's government on Tuesday accused rebel forces of using chemical weapons, with state media saying "terrorists" had fired "rockets containing chemical materials" in Aleppo province, killing 15 people.
"Terrorists fired rockets containing chemical materials on Khan al-Assal in Aleppo province, and preliminary information suggests 15 people were killed, mostly civilians," the state news agency SANA and Syrian state television said.
The accusation is the first such claim by the regime of President Bashar al-Assad against rebel forces, though the international community has warned the regime against deploying its own stocks of chemical weapons.
There are also concerns that the weapons could fall into the hands of militants, with the United States and Israel particularly concerned about the fate of the arms if the regime loses control over them.
Syria's chemical weapons stockpile, which dates back to the 1970s, is the biggest in the Middle East, but its precise scope remains unclear, according to analysts, and the regime has not acknowledged having the arms.
The country has hundreds of tons of various chemical agents, including sarin and VX nerve agents, as well as older blistering agents such as mustard gas, dispersed in dozens of manufacturing and storage sites, experts say.
But it remains unclear if the chemical weapons are mounted and ready to be launched on Scud missiles, if the chemical agents are maintained effectively, and whether the regime is able to replenish its chemical stocks.
Damascus has said it might use its chemical weapons if attacked by outsiders, although not against its own people.