File Photo: Russian Ambassador to the United Nations Vassily Nebenzia (C, front) addresses the Security Council before he vetoes a Security Council draft resolution at the UN headquarters in New York, on Oct. 24, 2017. (Xinhua/Li Muzi)

UNITED NATIONS, Nov. 15 (Xinhua) -- Russia and the United States were at odds Wednesday at the UN security council on whether to renew the mandate of an independent investigation mechanism tasked to determine who was responsible for the use of chemical weapons in Syria.

Russia last month vetoed a U.S.-sponsored draft resolution that would have extended for another year the mandate of the Joint Investigative Mechanism (JIM) of the Organization for the Prohibition of Chemical Weapons and the United Nations.

After that, the United States and Russia have circulated competing draft resolutions among council members for consideration.

"Intense negotiations are going on. We are still hopeful that there will be a solution to a continuation of JIM, maintaining the mandate," Olof Skoog, the Swedish ambassador to the United Nations, told reporters on Wednesday. "It's very late in the day, but we're not giving up."

On the two competing draft resolutions, he said, "We are encouraging the United States and Russia to find a compromise."

A JIM report, which came out two days after the Russian veto on Oct. 24, finds that the Syrian government and the Islamic State (IS) terrorist group were responsible for using chemical weapons in Syria.

The IS used sulfur mustard in a September 2016 attack in Umm Hawsh and the Syrian government was responsible for the release of sarin in an April 2017 attack in Khan Shaykhun, according to the report.

"There has been sufficient evidence of a credible and reliable nature to make its findings," Edmond Mulet, head of JIM, told the Security Council on Nov. 7.

But Russia questioned the methodology of JIM, particularly the fact that it did not carry out on-site visits. In an Oct. 31 letter to the president of the Security Council, Russian ambassador to the United Nations (UN) Vassily Nebenzia called the JIM report "amateurish in nature" and "based primarily on assumptions and a selective use of facts."

Russia, therefore, demands a modification of JIM's mandate, while the United States and its allies want to maintain the current JIM mandate.

Should negotiations fail, the Security Council would repeat last year's scenario, where the JIM mandate was not renewed on time, leading to disruptions in JIM's work. The Swedish ambassador saw "a good conversation going on" and said he was still hopeful.

It is not clear whether Russia will also put its draft resolution to vote in the Security Council. Asked on Monday whether his country would do so, Nebenzia said: "Let's see."

JIM was unanimously approved by the Security Council in 2015 and had its mandate extended last year, although the renewal was delayed.