UNITED NATIONS (Reuters) - Russia on Friday questioned the work and future of an inquiry into who is to blame for toxic gas attacks in Syria and said it would decide whether to support extending the mandate after investigators submit their next report to U.N. Security Council.

FILE PHOTO: A United Nations (U.N.) chemical weapons expert, wearing a gas mask, holds a plastic bag containing samples from one of the sites of an alleged chemical weapons attack in the Ain Tarma neighbourhood of Damascus, Syria August 29, 2013. REUTERS/Mohamed Abdullah/File Photo

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 U.N. Security Council in 2015 and renewed in 2016 for another year. Its mandate is due to expire in mid-November.

Mikhail Ulyanov, director of the Russian Foreign Ministry’s non-proliferation and arms control department, said there were “serious problems” with the work of the inquiry.

“In order to judge if it deserves an extension of the mandate, we need to see the report to be issued on the 26th of October and assess it,” Ulyanov told a briefing at the United Nations in New York.

“I ask myself what is the reason for the extension of the mandate of this mechanism if it is not capable and is not willing to fulfill its mandate,” he said. “We will wait for the report and then we will define our position.”

Several dozen U.N. diplomats attended the briefing, held by Russia to present its view on the “Syrian chemical dossier.”

U.S. Ambassador to the United Nations Nikki Haley said last week that renewing the mandate of the JIM should be the Security Council’s top priority. It was unclear when the United States planned to put forward a draft resolution to extend the inquiry.

Some U.N. diplomats said that a draft resolution could be put to a vote before the next JIM report is submitted. A resolution needs nine votes in favor and no vetoes by Russia, China, the United States, Britain or France in order to pass.

The JIM has already found Syrian government forces were responsible for three chlorine gas attacks in 2014 and 2015 and that Islamic State militants used mustard gas. It is due to report this month on who is to blame for an April 4 attack on the opposition-held town of Khan Sheikhoun that killed dozens.

A separate OPCW fact-finding mission determined in June that the banned nerve agent sarin had been used in the attack, which prompted the United States to launch missiles on a Syrian air base.

Syria agreed to destroy its chemical weapons in 2013 under a deal brokered by Russia and the United States. The Syrian government has repeatedly denied using chemical weapons during the country’s more than six-year civil war.