International diplomacy has failed to slow Syria’s crisis, which anti-regime activists say has killed more than 40,000 people since March 2011.
Also on Friday, Russia’s foreign minister said Moscow had proposed talks with the main Syrian opposition coalition, even though it has criticized Western countries for recognizing the group.
Sergey Lavrov told reporters that Russia has contacted the Syrian National Coalition for Opposition and Revolutionary Forces through the Russian Embassy in Egypt to suggest a meeting with coalition leader Mouaz al-Khatib.
Al-Khatib criticized the invitation.
‘‘If we don’t represent the Syrian people, why is he inviting us?’’ he said in an interview with Al-Jazeera TV, calling Assad’s ouster ‘‘a main condition in any negotiations.’’
‘‘The Syrian people haven’t heard one fair word from Russia to the Syrian people, especially to the children, innocent people and civilians who are killed every day with Russian weapons,’’ he said.
Russia is one of Assad’s strongest backers, although top officials have recently expressed some resignation to the idea that he could fall. Still, Russia opposes international calls for his ouster and wants a negotiated solution to the conflict.
The international envoy charged with pushing to end the civil war is due to meet Russian officials in Moscow this weekend.
During a visit to Damascus this week, Lakhdar Brahimi called for a transitional government.
The rebels have rejected his plan, and the Syrian government has not commented.
Associated Press writer Jim Heintz in Moscow contributed reporting.