U.N. confirms use of mustard, chlorine gas in Syrian civil war

The U.N.'s Organization for the Prohibition of Chemical Weapons (OPCW) said it has "utmost confidence" mustard gas was used on Aug. 21 in the town of Marea during fighting between Syrian rebels and the Islamic State.

The Islamic State is accused of using the gas, which "very likely" killed a baby. The OPCW investigated after hearing of the claim and later collected samples and interviewed two people affected by the exposure, as well as their doctors.