U.S. assertions that the Syrian government may be planning a chemical weapons attack complicate peace talks on Syria, RIA news agency quoted Russian Deputy Foreign Minister Gennady Gatilov as saying on Wednesday.

U.S. officials said on Tuesday Washington's warning to Syria's leadership against staging a chemical weapons attack was based on intelligence about what appeared to be active preparations at a Syrian airfield used for such an attack in April.

Gatilov warned the United States not to take unilateral actions in Syria.