Investigators have said Syrian government forces were behind a third chemical weapons attack last year. <br /><br /> In a report to the United Nations Security Council, military helicopters are said to have dropped barrel bombs containing chlorine gas in Syria’s north-west province of Idlib in March 2015. <br /><br /> The toxic chemical can kill by burning the victims lungs, drowning them in the resulting body fluids. <br /><br /> The finding sets the stage for a showdown between Russia and western UN council members over how to respond. <br /><br /> In addition to the bombing in Idlib, an earlier report also accused Bashar al Assad’s forces of two other chemical weapons attacks in 2015 and 2014. <br /><br /> The report follows the UN human rights chief’s condemnation over the humanitarian crisis in Aleppo. <br /><br /> Describing the city as a ‘‘slaughter house’‘, Zeid Raad Al Hussein said the siege and bombing of eastern districts of the city constituted ‘‘crimes of historic proportions.<br />
