The Organization for the Prohibition of Chemical Weapons has blamed Syria’s Army for killing 43 people and sickening dozens of others in a chemical weapons attack on the rebel-held city of Douma in 2018. In a new report, OPCW investigators say a Syrian Army helicopter dropped two yellow cylinders containing toxic chlorine gas on two apartment buildings in a civilian-inhabited area of Douma. The U.S. bombed Syria days after the alleged attack.

Syria’s Foreign Ministry said it “totally rejects” the OPCW report, and has accused rescue workers with the “White Helmets” organization of staging the attack at the behest of the United States. In 2019, two former OPCW employees leaked internal documents revealing there were conflicting views within the organization about what actually happened in Douma, leading some observers to conclude that the chemical attack might have been staged by Syrian rebels.