The UN Security Council has unanimously adopted a resolution to establish a panel to determine who used chemical weapons in Syria.The U.S.-drafted resolution on Friday asked UN Secretary-General Ban Ki-moon and the Organization for Prohibition of Chemical Weapons to set up a joint investigative panel within 20 days to identify attackers who used chlorine and other toxic agents in Syria.It sanctions the panel "to identify to the greatest extent feasible individuals, entities, groups, or governments who were perpetrators, organizers, sponsors or otherwise involved in the use of chemicals as weapons, including chlorine or any other toxic chemical" in the war-torn country.It also paved the way for holding to account specific organizations or individuals responsible for the deadly chlorine gas attacks.The resolution came to a vote after months of discussion with Russia, which is an ally of Syrian President Bashar al-Assad and has protected his regime from any Security Council action during the four-year civil war that has left at least 250,000 people dead.Its adoption is considered a significant shift in Moscow's stance regarding UN action on Syria.The U.S. and its allies, as well as civil rights groups, have repeatedly accused the Syrian regime of launching chlorine attacks through barrel bombs dropped from its helicopters.