Ban told the U.N. General Assembly that the international community also has a moral and political responsibility to deter further incidents and "ensure that chemical weapons can never re-emerge as an instrument of warfare."
Ban addressed the 193-member assembly on Friday on the final report by U.N. inspectors who investigated allegations of chemical weapons use in Syria.
They concluded that chemical weapons were probably used in four locations this year, in addition to the confirmed attack near Damascus in August that forced the government to abandon its secret chemical stockpile.
Ban said "any use of chemical weapons by anyone under any circumstances is a grave violation" of customary international law.
