Russia has warned Syria could descend into civil war if the UN Security Council backs a call for president Bashar al-Assad to quit.

The Security Council is considering an Arab League resolution which would order Mr Assad to stand aside amid the ongoing bloodshed in Syria.

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But Russia, a major supplier of arms to the Syrian regime, is opposing the move, saying it will veto any Security Council resolution that leads to foreign intervention.

"We all know that change is coming to Syria. Despite its ruthless tactics, the Assad regime's reign of terror will end," US secretary of state Hillary Clinton told the 15-nation council this morning.

"The question for us is how many more innocent civilians will die before this country is able to move forward.

"The United States urges the Security Council to back the Arab League's demand that the Syrian Government immediately stop all attacks against civilians and guarantee the freedom of peaceful demonstrations."

Arab League secretary-general Nabil Elaraby called on the council to take "rapid and decisive action", while Qatari prime minister Sheikh Hamad bin Jassim al-Thani warned that Syria's "killing machine is still at work" but said his nation was not calling for military intervention.

British foreign secretary William Hague also told the council the resolution "does not call for military action and could not be used to authorise it".

The Arab League proposal is also backed by permanent Security Council members France and Britain.

But Russian foreign minister Sergei Lavrov said earlier that Syrians should be able to decide their own future.

"It is up to the Syrians themselves to decide how to run the country, how to introduce the reforms, what kind of reforms, without any outside interference," he told the ABC's Lateline in an exclusive interview with Emma Alberici.

"Yes, we condemn strongly the use of force by government forces against civilians, but we can condemn in the same strong way the activities of the armed extremist groups who attack government positions."

Deputy foreign minister Gennady Gatilov said pushing the resolution through would be a "path towards civil war".

China, which like Russia has a veto in the council, also has reservations about the draft. Russia and China vetoed a European-drafted resolution in October that condemned Syria and threatened it with sanctions.

But French foreign ministry spokesman Bernard Valero, speaking before the council meeting, said France was hopeful a breakthrough is possible.

"We hope with this dramatic violence on the ground, and the commitment of the Arab League, some members of the UN Security Council will finally change their mind, will realise that the time has come to take its responsibility, and will allow the Security Council to move on this issue," he said.

The Security Council debate comes after a days of intense fighting between rebels and Syrian government forces in eastern suburbs of Damascus and in towns around the country.

More than 100 people are reported to have died in the violence, which broke out as government troops tried to recapture rebel-held areas following the departure of Arab League peacekeepers.

The opposition says most of the recent deaths have been in Homs, but there have been many others in Idlib, Rankous and Daraa, the town near the Jordanian border where the uprising began 11 months ago.

Sorry, this video has expired Sergei Lavrov talks to Lateline

Mr Lavrov denied that Russia was a friend of Mr Assad's, but said a "second Libya" would be a disaster.

"We're not a friend, we're not an ally of President Assad. We never said that President Assad remaining in power is the solution to the crisis," he said.

"But if there is no dialogue, then the question means only one thing, that you want a second Libya, and this will be a disaster for the Arab world and for world politics.

"The people who are obsessed with removing regimes in the region, they should be really thinking about the broader picture.

"I'm afraid that if this vigour to change regimes persists, we are going to witness a very bad situation - much, much, much broader than just Syria, Libya, Egypt or any other single country.

"We don't want to make this easy. We're going to prevent this type of development."

On the ground in Syria, opposition forces have called for a "day of mourning and anger" after the recent fighting.

The Syrian Observatory for Human Rights says more than 100 people have been killed over the past two days as government forces push back rebel fighters from the outskirts of Damascus and several other cities.

The group says 55 of those killed were civilians.

The government says it has eliminated resistance by rebels on the edge of Damascus after three days of fighting.

But opposition fighters say they have pulled back from the capital for strategic reasons and will launch guerrilla attacks.

One activist says government troops have been moving through several Damascus suburbs, making hundreds of arrests and looting houses.

ABC/wires