article_snippet.sent: The global chemical weapons watchdog is also investigating allegations the gas was used to carry out fatal attacks in Syrian villages.
article_snippet.sent: Activists have accused the Syrian regime of using chlorine - a toxic agent that can be considered a chemical weapon - on civilian areas in the past.
article_snippet.sent: There is also evidence to suggest ISIS is using chlorine gas as a chemical weapon in ISIS battle, Kurdish authorities have claimed.
article_snippet.sent: In October chlorine-filled cylinders were also discovered during clashes in the towns of Balad and Duluiya.
article_snippet.sent: And reports from the Syrian border-town of Kobani suggested the extremist group added chlorine to an arsenal that already included heavy weapons and tanks looted from captured military bases earlier this year.