Russia on Thursday warned of "bloody chaos" in Syria should peace talks led by UN-Arab League envoy Lakhdar Brahimi fail to end the 21-month conflict estimated to have claimed more than 45,000 lives.

"The alternative to a peaceful solution is bloody chaos. The longer it continues, the greater its scale -- and the worse things get for all," Foreign Minister Sergei Lavrov told the Interfax news agency.

Lavrov's comments followed his meeting earlier in the day with a senior Syrian delegation led by Deputy Foreign Minister Faisal Muqdad.

Russia remains Syria's most important international ally and is one of the few nations to have unlimited access to Syrian President Bashar al-Assad's government.

Lavrov's meeting with the Syrians came as Brahimi wound down several days of talks in Damascus by calling for "real change" and the quick introduction of a transition government "with all powers".

Assad's government has still not responded to Brahimi's call.

But the armed opposition immediately rejected any transition plan that would see either Assad or his immediate cohorts retain their positions of authority.

Brahimi will meet Lavrov in Moscow on Saturday in hopes of convincing Russia to do all it can to make sure that Assad accepts an accord that would gradually ease him from power.

Lavrov did not disclose the full details of his talks with the visiting Syrian delegation.

But he conceded that hopes were fading for a Russian-backed initiative drafted in Geneva in June that made no explicit call on Assad to step down -- an alternative the ruling regime appeared to accept.

"Considering what is happening in Syria, the chances for such a solution based on the Geneva communique... are diminishing," Lavrov told Interfax.

"But they still exist, and we must fight for them," Lavrov added.

He said recent tri-party consultations that included Brahimi and US officials showed that chances of a peaceful solution based on the Geneva agreement "still exist".

"We need coordinated action from all the parties, and they must speak in one voice," Russia's top diplomat said.

Russia has always insisted it was not propping up Assad's regime but only pursuing a defence of international law that rejects foreign intervention in domestic disputes.

Lavrov announced earlier this month that Moscow had no intention of either asking Assad to step down or hosting the embattled Syrian leader should he decide to seek exile.

But it has vowed to press on with its campaign to establish direct dialogue between the warring sides.

Egyptian Foreign Minister Mohamed Amr was also due in Moscow on Thursday on a visit that will include talks and a news conference with Lavrov on Friday.