Deputy Foreign Minister Gennady Gatilov said on Twitter that such attempts would contradict the peace plan for Syria approved by world powers in Geneva in June.
U.S. Secretary of State Hillary Rodham 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.
"Attempts by Western sponsors of the Syrian opposition to enforce a list of the nation's future leadership from the outside contradict the Geneva agreements," Gatilov said. "The Geneva communique says that a transitional governing body should be formed on the basis of mutual accord of the government and the opposition."
Russia has been the main supporter of Syrian President Bashar 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.
Earlier this week, Russia's Foreign Minister Sergey Lavrov reaffirmed Moscow's rejection of calls for Assad's ouster, saying that it would only exacerbate the conflict. He said that he and other Russian diplomats have urged Syrian opposition groups to name their representatives for talks with the government.
Russia in the past has hosted various members of the Syrian opposition and has not voiced a preference.