Russian Foreign Minister Sergei Lavrov said Russia would veto a U.N. resolution calling to extend the mandate to for observers in Syria calling it blackmail.
He went on to explain that the observer program is fine, but the threat of sanctions if Syria does not accept the Observers amounts to blackmail, since it is also tied to Annan's peace plan.
"To our great regret, we are seeing elements of blackmail," Lavrov told a news conference before Annan started a two-day visit that will include talks on Tuesday with President Vladimir Putin. "This is a counter-productive and a dangerous approach."
Russia is Syria's largest arms supporter and has resisted western efforts to remove Syrian President Bashar al-Assad from power saying "he will not go" on his own and that any planned negotiations must include Assad.
Russia did say last week it would not deliver any more arms or other weapons to Syria until this conflict is resolved.