UNITED NATIONS (AP) – The U.N. Security Council unanimously adopted a resolution Friday aimed at identifying those responsible for using chlorine and other chemical weapons in attacks in Syria that have killed and injured a growing number of civilians over the past two years.

The resolution, negotiated primarily by the United States and Russia, establishes an international investigative body that would assign blame for any chemical weapons attacks during the Syrian conflict, now in its fifth year, so that the perpetrators can be brought to justice.

A chemical weapon attack on a Damascus suburb killed hundreds of civilians on Aug. 21, 2013 and led the Security Council to demand the destruction of Syria’s chemical weapons and the equipment used to produce them. But there have been numerous reports of continuing use of chemicals as weapons in Syria since then, especially chlorine-filled barrel bombs.

The Syrian government denies using chemical weapons, a point reiterated Friday by Syria’s U.N. Ambassador Bashar Ja’afari, who blamed “terrorist” groups.