Syria’s capital Damascus has been the scene of violent clashes between rebels and government forces for the second consecutive day.
The regime is trying to regain control of several districts. Opponents said all roads in and out of the city had been blocked.
Russia meanwhile has accused the West of blackmail over Syria.
In Moscow Foreign Minister Sergei Lavrov said
the future of the UN’s observer mission was being linked to Russia’s opposition to a draft resolution.
He urged countries to back Moscow’s own resolution which carries no threat of UN sanctions against Damascus.
Russia, he said, did not support Bashar al-Assad and did not have the influence to persuade him to step down because the Syrian leader had the support of much of the population.
Russia believes the West’s view of the Syrian conflict is too simplistic.
Last week’s events in the village of Tremseh are an example. First described as a massacre of civilians, later reports said most of those killed were armed rebels.
The government has denied using heavy weapons; UN observers disagree.
“In this attack there was a use of heavy weapons on population centres. Our observers confirmed the use of direct and indirect weapons including artillery, mortar shells and small arms,” said UN spokeswoman Sausan Ghosheh.
Last week Syria’s opposition was unable to shift Moscow’s position. On Monday UN envoy Kofi Annan was in the Russian capital.