UNITED NATIONS — The U.N. Security Council failed to agree Tuesday on whether Syria merited sanctions over the use of chemical weapons, with Russia questioning the evidence from an independent commission that found government forces were behind at least two such attacks.

Council members met to discuss the findings of an international team of inspectors that determined that both the Syrian government and Islamic State militants were responsible for chemical attacks carried out in 2014 and 2015.

But Russian Ambassador Vitaly Churkin, whose country is a close ally of the Syrian government, said it was too early to consider implementing a September 2013 council resolution authorizing sanctions that can be militarily enforced for any use of chemical weapons in Syria.

“Clearly there is a smoking gun. We know that chlorine most likely has been used — that was already the finding of the fact finding mission before — but there are no fingerprints on the gun,” Churkin said following the closed-door session.

“There is nobody to sanction in the report which has been issued,” he said. “It contains no names, it contains no specifics. … If we are to be professional we need to question all the conclusions.”

Churkin said, however, that he was pleased the report had confirmed the use of chemical weapons by the Islamic State group.

Heading into the meeting, U.S. Ambassador Samantha Power called the report “a landmark” and said she expected a Security Council resolution “soon.”

“It is the first official independent confirmation of what many of us … have presented substantial evidence of for a long time, and that is a pattern of chemical weapons use by the Syrian regime,” Power said. “It is incumbent on the council to act swiftly to show … we were serious about there being meaningful accountability.”

In September 2013, Syria accepted a Russian proposal to relinquish its chemical weapons stockpile and join the Chemical Weapons Convention. That averted a U.S. military strike in response to an alleged chemical weapons attack that killed hundreds in the Damascus suburb of Ghouta.

Russia has blocked sanctions and other council action against President Bashar Assad’s government — but Moscow did support the establishment of the Joint Investigative Mechanism, charged with determining who was responsible for the attacks and paving the way for possible punishment.

The inspectors investigated nine cases in seven towns and determined the Syrian government was responsible for two attacks involving chlorine gas and the Islamic State group — which is already under U.N. sanctions — for one attack involving mustard gas.

They said three more attacks pointed toward government involvement but weren’t conclusive, and described three others as inconclusive.

Virginia Gamba, who headed the inspection team, defended their methodology but conceded that it was difficult to prove the use of chlorine, which is commercially available and evaporates quickly.

Because of her team’s narrow mandate, she said inspectors only scratched the surface of chemical weapons use in Syria, adding that they were “acutely aware of the ongoing use of chemicals as weapons in the Syrian Arab Republic.”

Inspectors said that between December 2015 and August 2016 they received more than 130 new allegations from U.N. member states of the use of chemical weapons or toxic chemicals as weapons in Syria. They said the attacks involved sarin, mustard gas, VX nerve gas, chlorine, and 61 other toxic chemicals.

Syrian Ambassador Bashar Ja’afari dismissed the report’s findings as biased.

“The conclusions contained in the report were totally based on statements made by witnesses presented by the terrorist armed groups,” he said. “Therefore, these conclusions lack any physical evidence.”

Ahead of the meeting, Human Rights Watch called on the Security Council to urgently impose sanctions on the Syrian government and to refer the case to the International Criminal Court, but acknowledged that might be difficult in the Security Council where Russia holds a veto.

“This has been a political minefield for five and a half years but we have something different, we have a U.N.-backed mechanism with a report,” said Louis Charbonneau, U.N. director at Human Rights Watch. “We have it in black and white that the Syrian Government and ISIS are responsible for using chemical weapons, it’s a crime and the Security Council has many tools it can use, so we expect them to use them all.”