MOSCOW — A senior Russian diplomat has warned the West against trying to predetermine a future leadership of Syria.

Deputy Foreign Minister Gennady Gatilov said on Twitter Friday that such attempts would contradict guidelines for a political transition in Syria approved in Geneva in June.

U.S. Secretary of State Hillary Clinton said Wednesday that the administration would push for a shakeup in the Syria opposition leadership so that it better represents fighters on the frontline.

Washington believes that a revamped rebel leadership could rally wider international support and prevent extremists from hijacking the rebellion.

Russia has been the main supporter of Syrian President Bashar al-Assad's government, shielding it from U.N. sanctions over a crackdown on the 19-month uprising, in which at least 36,000 people have been killed, according to opposition activists.