MOSCOW (Reuters) – Russia opposes a draft U.N. resolution to extend the mandate of an international inquiry into chemical weapons attacks in Syria, Russian Deputy Foreign Minister Sergei Ryabkov said on Wednesday.

Ryabkov’s comments came hours after Russia rejected a report by the international inquiry blaming the Syrian government for a deadly toxic gas attack, casting doubt on the U.N. Security Council’s ability to extend the investigation’s mandate before it expires next week.

Russia last month cast a veto at the United Nations Security Council against renewing the investigation’s mandate.

“I stress that we are in no way raising the question of ending this structure’s activities,” RIA state news agency quoted Ryabkov as saying. “We are in favor of its maintenance, but on a different basis.”

The draft U.N. resolution by the United States says Syria must not develop or produce chemical weapons, and it calls on all parties in Syria to provide full cooperation with the international probe.

The investigation by the United Nations and the Organization for the Prohibition of Chemical Weapons — known as the Joint Investigative Mechanism (JIM) — was unanimously created by the 15-member Security Council in 2015 and renewed in 2016 for another year. Its mandate is due to expire in mid-November.

The investigation found that Syrian President Bashar al-Assad’s government was to blame for a chemical attack on the opposition-held town of Khan Sheikhoun that killed dozens of people in April, according to a report sent to the Security Council on Oct. 26.

Russia, whose air force and special forces have bolstered the Syrian army, has said there is no evidence to show Damascus was responsible for the attack. Moscow maintains that the chemicals that killed civilians belonged to rebels, not Assad’s government.

(Reporting by Gabrielle Tétrault-Farber; Editing by Angus MacSwan)