Syrian opposition figures are set to begin on Monday four days of talks with the regime on finding ways to end the nearly four-year conflict, amid a boycott by the main exiled opposition bloc.
Moscow says the aim of the conference is to find ways to restart peace talks that collapsed in Geneva last year.
The war in Syria, which began in 2011 following peaceful protests calling for reforms and then the removal of Assad, has killed more than 200,000 people, according to the United Nations.
Russia’s longstanding proposals for a peace plan do not require Assad to leave power, which Assad's main opponents consider the basis for any talks.
Assad himself, speaking to a Czech magazine in an interview published earlier this month, said the purpose of the conference is to discuss “the unity of Syria, containing terrorist organization’s [and] supporting the army.”