Russia insists that all chemical weapons in Syria, including chemical arms components possibly held by Syrian opposition forces, should be destroyed, the Russian Foreign Minister said, according to RIA Novosti.

Speaking after a meeting with U.S. Secretary of State John Kerry in New York, Sergei Lavrov said “both the Russian and the American side stressed [during the talks], that all chemical weapons in Syria should be destroyed.”

“There are serious concerns that the opposition might possess separate components of those harmful substances,” he said.

Russia’s top diplomat said the meeting with Kerry was “productive” and that Russia and the United States share a common approach to what should be done in the future.

"The talks were productive, we have a common understanding of what should be done next, and that it should be done on the basis of the framework agreement reached in Geneva,” Lavrov said.

Washington and Moscow are expected to clash at the UN General Assembly later this week over the terms of a Security Council resolution that would enforce Syria’s compliance with a US-Russian plan for the Syrian government to hand over its chemical arsenal.

UN chemical weapons inspectors are expected to return to Syria on Wednesday.

Last week, they confirmed the nerve agent sarin was used in that attack.

The inspectors were not asked to ascertain who fired the artillery rockets which hit parts of the Ghouta agricultural belt, but Western powers have claimed that it could only have been Syrian government forces.

UN war crimes investigator say there have been 14 alleged cases of chemical weapons or chemical agent use in Syria since the uprising against President Bashar al-Assad began in 2011.

On Tuesday, Ryabkov told the Russian parliament that the UN inspectors were expected to resume their work imminently.

"We are pleased that our persistent calls for the return of UN experts to Syria for the investigation of other episodes have borne fruit," he said.

Last week, he criticized the UN inspectors' report, saying it was "distorted" and "one-sided", and based upon "insufficient" information.