Russia has accused the West of "blackmail" as it sought to deflect calls to impose sanctions on Syria.

Foreign Minister Sergei Lavrov staked out a tough position before talks in Moscow with UN envoy Kofi Annan, dismissing international pressure on Russia and China to stop propping up Syrian President Bashar al-Assad.

His comments are likely to dim Western diplomats' hopes that Moscow is trying to find a face-saving way to drop its support for Assad and accept that he should have no role in a power transition.

"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."