The resolution asks United Nations chief Ban Ki-moon and the head of the Organization for the Prohibition of Chemical Weapons (OPCW) to make recommendations within 20 days for the establishment of an investigative body, "to identify to the greatest extent feasible individuals, entities, groups, or governments" involved in any chemical attacks in Syria.

The adoption of the resolution came after the United States struck a deal with Russia, a strong backer of Syrian President Bashar al-Assad, on a formal request to the U.N. to assemble a team of investigators to lay blame for toxic gas attacks in Syria.

US Ambassador to the United Nations Samantha Power said it was vital that those responsible for chemical attacks be held accountable.

"Pointing the finger matters," Power told the council after the vote.

Attributing responsibility for poison gas attacks in Syria's four-year conflict could pave the way for action by the 15-member Security Council. The body has already threatened consequences for such attacks, which could include sanctions.

Power told reporters Friday's vote was a "modest step" toward ending the impunity Syria's war criminals have enjoyed.

But she acknowledged that accountability for crimes in Syria appeared a long way off after Russia and China vetoed a Western proposal last year to refer the Syrian conflict to the International Criminal Court.

The council is expected to authorize the investigative team for one year once it receives Ban's recommendations.

Government and opposition forces have denied using chemical weapons. Western powers say the Syrian government has been responsible for chemical attacks, including chlorine attacks. The Syrian government and Russia have accused rebel forces of using poison gas.

Syrian Ambassador Bashar Ja'afari told the council that his country has been the victim of chemical attacks by Islamic State militants and the al Qaeda-affiliated Nusra Front.

Syria agreed to destroy its chemical weapons in 2013 in a bid to avoid U.S. military strikes threatened over a sarin gas attack that killed hundreds of civilians. The OPCW has since found chlorine has been "systematically and repeatedly" used as a weapon, though it is not mandated to lay blame.

A separate UN investigation had previously determined that sarin gas has been used repeatedly in Syria to deadly effect, but that inquiry was also barred from assigning blame.

Chlorine's use as a weapon is prohibited under the 1997 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.