Chemical weapons investigators have concluded "with a high degree of confidence" that chlorine gas was used as a weapon against three opposition-controlled villages in Syria last year, according to a report obtained Tuesday by The Associated Press(AP).
The chlorine gas attacks affected between 350 and 500 people and killing 13, according to the news agency.
The third report by a fact-finding mission from the Organization for the Prohibition of Chemical Weapons (OPCW) didn't apportion blame but said 32 of the 37 people interviewed "saw or heard the sound of a helicopter over the village at the time of the attack with barrel bombs containing toxic chemicals."
The investigators said 26 people heard the distinctive "whistling" sound of the falling barrel bombs containing toxic chemicals and 16 visited the impact sites and saw the bombs or their remnants.
They said 29 people smelled "the distinctive odor of the gas cloud" released after the bombs hit the ground, mainly describing it "as intense, chlorine-like, similar to cleaning material used to clean toilets, but much stronger."
The report includes a description of 142 videos and 189 pieces of material obtained by the investigators as well as photos of impact sites and the inner chlorine cylinder from a barrel bomb, noted AP.
The mission was established by the OPCW on April 29 to establish the facts surrounding allegations of the use of chlorine "for hostile purposes" in Syria. Chlorine gas is readily available and is used in industry around the world, but can also be used as a weapon.
Activists in Syria said several months ago that over 100 people had been killed in a chlorine gas attack in the town of Talmenes in Idlib province, prompting the United Nations Security Council to call for an investigation into the alleged attack. Since then there were reports of other such attacks.
U.S. Secretary of State John Kerry has warned the Bashar Al-Assad regime it would be held to account for using chlorine gas against civilians.
Syria, however, has denied ever using chemical weapons or chlorine during the country’s brutal civil war, blaming “terror groups”, the Syrian government’s term to describe rebels, for using such weapons
The UN Security Council has been intensely involved in the issue of alleged chemical weapons use in Syria.
After an August 2013 sarin gas attack near Damascus in which more than 1,400 people were killed, the Security Council unanimously adopted a resolution backed by the U.S. and Russia on September 27, 2013, ordering Syria's chemical weapons stockpile to be destroyed.