Russian Foreign Minister Sergei Lavrov says Moscow's concern about Syria's conflict is growing but that Moscow will continue to oppose the outside use of force.
However, Lavrov told reporters in Moscow on June 9 that Russia would not oppose Syrian President Bashar al-Assad's departure if it is decided by Syrians themselves.
Russia is pushing for an international conference on Syria as world outrage grows over massacres of civilians by loyalist Syrian militiamen and troops.
On June 8, U.S. Secretary of State Hillary Clinton met with international envoy Kofi Annan in Washington to discuss how to salvage a plan to end 15 months of bloodshed in Syria.
Annan repeated his call for "additional pressure" on Syria.
"Syria is a real challenge, and I'm really grateful to have the opportunity to discuss with Secretary of State Hillary Clinton the issues involved in how we can put additional pressure on the government, on the parties, to get the plan implemented," Annan said.
Meanwhile, activists say Syrian troops have shelled the southern city of Daraa, killing at least 17 people. The Britain-based Syrian Observatory for Human Rights says dozens of people were also wounded in the shelling early on June 9.
Daraa is the city where the uprising against Assad's regime began in March last year.
The deaths in Daraa came amid an international outcry over the killings of civilians on June 6 in an assault by alleged loyalist militiamen and troops on the village of Mazraat al-Qubeir.
UN observers who visited the village on June 8 said they saw blood on walls, smelled "burned flesh," and saw evidence that a "horrific crime" had been committed, but were unable to confirm reports that nearly 80 people had been killed.
The government has denied responsibility, accusing unnamed "terrorist groups" of committing the massacre.