"To our great regret, we are witnessing elements of blackmail," Foreign Minister Sergei Lavrov told a news conference over moves to end 16 months of violence that the opposition says has claimed more than 17,000 lives.

"We are being told to either agree to the approval of a resolution that includes Chapter 7 (that provides for possible sanctions), or we refuse to extend the mandate of the observer mission.

"We view this as a completely counterproductive and dangerous approach," Lavrov said ahead of talks later Monday with UN-Arab League crisis envoy Kofi Annan.

Lavrov also stressed that it was "unrealistic" for Western powers to expect Russia to convince Syrian President Bashar al-Assad to step down simply because Moscow is a long-standing ally of the Damascus regime.

"We hear comments like the 'key to a Syrian solution is to be found in Moscow'. Then it is explained to us, when we ask about this, that it means that we (Russia) have to convince Assad to step down of his own accord." But he said: "It is simply unrealistic. And it is not a question of our inclinations, our sympathies or our antipathies.

"He (Assad) will not leave power. And this is not because we are protecting him but because there is a very significant part of the Syrian population behind him," Lavrov told reporters.

Lavrov last week received top Syrian opposition leaders in Moscow but lamented that their demands were still "radical" as they were demanding full regime change.

"So far we have not succeeded in getting through to them (the opposition) the necessity of renouncing radical positions. They are continuing to say that a revolution is in progress." Lavrov against stressed that Russia was not supporting Assad as an individual but Syrians' right to determine their future under Annan's peace initiative.

"I will repeat -- we are not supporting Bashar al-Assad. We are supporting what everyone else is -- the peace plan of Kofi Annan."