Russian President Vladimir Putin said Wednesday that Turkish counterpart Recep Tayyip Erdogan and Iran's President Hassan Rouhani have agreed to a "congress" of Syria's regime and opposition forces in Sochi, aimed at boosting fraught UN peace talks in Geneva.

The congress would "gather representatives of different political parties, internal and external opposition" to discuss "the parameters of the future state," Putin said, adding that it would be "a stimulus for activating the efforts for Syria regulation in the framework of the Geneva process."