Russia voiced support on Saturday for international peace envoy Lakhdar Brahimi but insisted that Syrian President Bashar al-Assad's exit cannot be a precondition for a deal to end the conflict in Syria.

A Russian Foreign Ministry statement after talks on Friday in Geneva with the United States and Brahimi reiterated calls for an end to the violence in Syria.

"As before, we firmly uphold the thesis that questions about Syria's future must be decided by the Syrians themselves, without interference from outside or the imposition of prepared recipes for development," the Russian Foreign Ministry said.

It said the "priority task" is to immediately stop any violence and bloodshed and provide humanitarian aid for displaced people and refugees. As a key Damascus ally, Russia also reiterated its support for a transitional plan that was agreed on in Geneva in June.

"At the same time, it is necessary to secure the launch of a political transition process in Syria, which is aimed at enshrining in law guaranteed and equal rights for all ethnic-confessional groups of this country," it added.

Russia and the United States disagreed over what the June agreement meant for Assad. Washington said it sent a clear signal he must go and Russia contended it did not.

On Saturday, Qatar made a fresh call for an Arab force to end the bloodshed in Syria if Brahimi's efforts fail, according to Al Jazeera television in Doha.

"It is not a question of intervention in Syria in favor of one party against the other, but rather a force to preserve security," Qatari Prime Minister and Foreign Minister, Sheikh Hamad bin Jassim al-Thani, said in an Al Jazeera broadcast.

The UN estimates that more than 60,000 Syrians have been killed since the revolt broke out in March 2011 and says more than 600,000 Syrians are registered as refugees in the region.

A report by the UN High Commissioner for Refugees on Saturday said the number of Syrian refugees receiving support from the Lebanese government and non-governmental aid agencies has reached nearly 200,000.

The report said more than 139,000 refugees have been registered and about 55,000 are waiting to be officially registered.

Syrian government aircraft bombed outer districts of Damascus on Saturday after being grounded for a week by stormy weather, said opposition activists in the capital.

The weeklong respite from airstrikes was marred by snow and thunderstorms that affected millions who were displaced by the conflict, which has now reached every region of Syria.

On Saturday, the skies were clear and jets and helicopters fired missiles and dropped bombs on towns to the east of Damascus, where rebels have pushed out Assad's ground forces, according to observers.

Rebels control large swathes of rural land around Syria but are stuck in a stalemate with Assad's forces in cities, where the army has reinforced positions.

State TV said government forces had repelled an attack by terrorists on Aleppo's international airport, which is now used as a helicopter base.

Opposition activists said a military escalation and the hardship of winter have accelerated the death toll.

Rebel forces have acquired more powerful anti-tank and anti-aircraft weapons during attacks on Assad's military bases.