In its latest report on the systematic use of banned munitions in Syria's civil war, the Organisation for the Prohibition of Chemical Weapons (OPCW) did not say which party was behind the attack on Saraqib, which lies in rebel-held territory in the province of Idlib.
Banned chlorine munitions were likely dropped on a Syrian neighborhood in February, an global body on chemical weapons said on Wednesday, after laboratory tests confirmed the presence of the toxic chemical.
In a statement released on Wednesday, the OPCW said its fact-finding mission had determined that "chlorine was released from cylinders by mechanical impact in the al-Talil neighborhood of Saraqib" city on February 4, 2018.
Eleven people had to be treated for breathing difficulties on February 4 after Syrian regime raids on Saraqeb, the Britain-based Syrian Observatory for Human Rights said at the time. Only Syrian government forces are known to have helicopters.
About the attack with the use of chlorine gas near the city of Saraqib announced on 6 February, the head of the press service of the U.S. Department of state Heather Nauert.
The samples tested positive for precursors needed to make the nerve agent sarin, he said.
Last month, Russian Federation held a press conference close to the OPCW headquarters in The Hague, at which it produced witnesses that claimed no chemical weapons attack had occurred, and that any choking had been due to dust inhalation.
The group said it came to its conclusion based on the presence of two cylinders at the site, which were determined to previously contain chlorine, along with witness testimony and environmental samples that demonstrated the unusual presence of chlorine. The FFM has previously confirmed with a "high degree of confidence" the use of chlorine, sulfur mustard, and sarin as weapons.
Most recently, a large-scale suspected chemical attack on the town of Douma killed more than 40 people in April.
Before the panel's mandate ran out late previous year, it also found the Syrian military to blame for at least three chemical attacks in villages in 2014 and 2015. However, its mandate is only to verify whether chemical weapons have been used, not to establish responsibility.