Russia is accusing the U.S., Britain and France of intentionally making a large number of groundless allegations of chemical weapons use in Syria in order to complicate efforts to arrange a U.N. investigation.

Russia's U.N. Ambassador Vitaly Churkin made the accusation Thursday following an announcement that Swedish chemical weapons expert Ake Sellstrom and U.N. disarmament chief Angela Kane will head to Damascus at the Syrian government's invitation, to discuss terms of a possible investigation.

Churkin also disputed a U.S. State Department statement that Russia, Syria's closest ally, is blocking an investigation. He insisted that Russia has promoted an investigation of "credible allegations" and stressed that a decision on a probe is up to the Syrian government and the U.N. secretary-general — not Moscow.