The United Nations Security Council has unanimously approved a one-year extension of an international inquiry to determine blame for chemical weapons attacks in Syria.
The inquiry was expanded at Russia's request on November 17 to focus more on the "terrorist chemical threat" within the region.
The joint inquiry by the United Nations and the Organization for the Prohibition of Chemical Weapons, launched by the council a year ago, has already found that Syrian government forces were responsible for three chlorine gas attacks and that Islamic State militants had used mustard gas.
Syria's government has denied the charges.
France, Britain, and the United States said they hope to start negotiations on a draft resolution to punish those blamed for the attacks, likely with UN sanctions.
But Russia, which has blocked such action against Syria in the past, contends the inquiry's findings are not convincing enough to lead to sanctions.
Chlorine's use as a weapon is prohibited under the Chemical Weapons Convention, which Syria joined in 2013. If inhaled, chlorine gas turns to hydrochloric acid in the lungs and can kill by burning lungs and drowning victims in the resulting body fluids.