Updated

Russia has vetoed a U.S.-drafted resolution to extend the mandate of experts trying to determine who was responsible for chemical attacks in Syria.

Russia's U.N. Ambassador Vassily Nebenzia then withdrew a rival Russian resolution — which was opposed by the United States and other Security Council members — on procedural grounds.

The result of Thursday's vote means that the Joint Investigative Mechanism, known as the JIM, will cease operations when its current mandate expires at midnight Thursday.

This will be a serious blow to efforts to hold those responsible for chemical weapons attacks in Syria accountable.

Both the U.S. and Russia said they wanted the JIM to be extended, but Russia insisted on changing its mandate, which the Trump administration and other council members rejected.