Syrian opposition leaders meeting with officials in Moscow say they were encouraged by Russian statements supporting further democratization in Syria.
Haytham Manna, spokesman for the Arab Commission for Human Rights, said Moscow "has all the necessary levers to apply pressure" on Syrian President Bashar al-Assad's government and "help" UN envoy Kofi Annan's mission.
Earlier on April 17, Russian Foreign Sergei Lavrov criticized unspecified "external forces" for undermining efforts to bring peace to Syria.
UN Secretary-General Ban Ki-moon, meanwhile, said the Syrian government must ensure that UN observers are able to move freely to monitor the country's shaky cease-fire.
Ban called the cease-fire "very fragile," but said it was essential that it hold so that an "inclusive political dialogue can continue."
He said opposition forces "should also fully cooperate."
An advance team of six observers arrived in Damascus on April 15.
Also, Beijing announced that Syrian Foreign Minister Walid Muallem will visit China on April 19.
China, together with Russia, vetoed two UN Security Council resolutions that were critical of Assad.
Reports say violence has dropped by a large degree in Syria since the truce took effect on April 12.
However, there are pockets of violence, especially in Homs where government shelling has raised doubts about Assad's commitment to Annan's plan to end 13 months of violence and launch talks on the country's political future.