(NBC News) – In recent weeks, the United States has accused Syria of repeatedly using chlorine gas as a weapon. Rebel-held areas of the Ghouta region were hit in a major chemical attack in 2013.
Last year, a joint inquiry by the U.N. and the Organization for the Prohibition of Chemical Weapons (OPCW) found the Syrian government was responsible for an April 4, 2017 attack using the banned nerve agent sarin in the opposition-held town of Khan Sheikhoun, killing dozens of people.
