International diplomacy has failed to stop the violence, and world powers remain deeply divided over who is responsible and how to stop it. The U.S. and many Western nations have called on Assad to leave power, while Russia, China and Iran have stood by the regime.
Lavrov objected to the text of a Western-backed resolution that calls for sanctions and invokes Chapter 7 of the U.N. Charter, which can be enforceable militarily.
He said Russia had been told that if it opposed the resolution, Western nations would not extend the mandate of a U.N. mission sent to Syria to monitor a cease-fire.
"We consider it to be an absolutely counterproductive and dangerous approach," Lavrov said.
International envoy Kofi Annan, who has made little progress in brokering a political solution in Syria, met Russian leaders in Moscow on Monday. The meeting — the latest in Annan's efforts to save his faltering peace plan — comes a day after the conflict crossed an important symbolic threshold, with the international Red Cross formally declaring it a civil war, a status with implications for potential war crimes prosecutions.
Monday's fighting suggested that deep cracks were appearing in the tightly controlled facade of calm that has insulated Damascus from violence throughout the uprising.