Russia is clashing with Western nations over a report blaming Syria for a chemical weapons attack that killed about 100 people, with Moscow dismissing its findings as "mythical or invented" and the U.S. backing its finger-pointing at President Bashar Assad's regime.

The debate in the Security Council during Tuesday's meeting on the report reflected the sharp differences between Russia, Syria's most important ally, and Western countries that have backed Assad's opponents.

It also raised serious questions about whether the mandate of the experts who issued the report will be renewed — and whether anyone in Syria will ever be held accountable for using chemical weapons, which are banned internationally.

Russia and the United States have circulated rival resolutions to extend the experts' body, known as the Joint Investigative Mechanism.