A UN Security Council resolution on Syria could mention Chapter VII of the UN Charter which allows force or tough sanctions, but only as a measure that could be invoked if an accord on chemical weapons is violated, a top Russian diplomat said Tuesday.

"Chapter VII can be mentioned only as an element of the measures against violators... if there is a refusal to cooperate, carry out obligations or if someone, it does not matter who, uses chemical weapons," Deputy Foreign Minister Sergei Ryabkov said.

Ryabkov expressed satisfaction that UN chemical weapons experts would be returning to Damascus "tomorrow, September 25" to investigate a chemical weapons attack outside Damascus in August, the Interfax news agency said, quoting comments in parliament.