Russian Foreign Minister Sergei Lavrov said Wednesday that next month's Russia-led peace talks in Sochi have "broad support" among the Syrian people and are meant to lay the groundwork for a U.N.-brokered peace process.
Lavrov's comments come after a collection of 40 Syrian rebel groups said Russia was trying to circumvent the U.N. peace process and that they would not attend the Sochi talks.
The rebels said Russia wants them to give up their demand that Syrian President Bashar al-Assad step down.
"We reject this and we affirm that Russia is an aggressor that has committed war crimes against Syrians," a rebel statement said Tuesday. "Russia has not contributed with a single move to alleviate the suffering of the Syrian people and it has not pressured the regime it claims it guarantees to move an inch toward any real path toward a resolution."
The rebels say the meditator in peace talks has to be a neutral and honest broker. They say Russia, as Syria's most powerful ally, is not.
The Syrian government has said it will attend the Sochi talks. Turkey, which supports the opposition, also plans to go, but says Kurdish groups should not be invited.
The Syrian Kurds' Democratic Union Party says it has a right to take part in the peace negotiations.
Turkey considers the PYD and its armed faction, the People's Protection Units, terrorist groups because of their ties to Kurdish separatists in Turkey.
U.N.-brokered peace negotiations in Geneva along with parallel talks involving Russia, Turkey, Iran, have made only minor progress toward ending Syria's six-year long civil war.