The top U.S., British and French diplomats are urging the U.N. Security Council to renew the mandate of experts charged with determining who was responsible for chemical weapons attacks in Syria.

U.S. Secretary of State Rex Tillerson, British Foreign Secretary Boris Johnson and French Foreign Minister Jean-Yves Le Drian also called for those responsible to be held accountable.

Their joint statement Wednesday follows the latest report by the experts blaming Syria for an attack using sarin that killed about 100 people and the Islamic State extremist group for an attack using mustard gas.

The report was strongly supported by the Western powers, but Russia on Tuesday sharply criticized the experts' for blaming Syria.

Russia and the U.S. have submitted rival resolution to extend the experts' mandate which expires Nov. 16.