UNITED NATIONS (AFP) - The Syria conflict has reached "unprecedented levels of horror," peace envoy Lakhdar Brahimi said on Tuesday, calling on the United Nations (UN) Security Council to act to end the carnage.

The UN-Arab League envoy told the 15-member council that President Bashar al-Assad's legitimacy has been "irreparably damaged" by the 22-month-old conflict but that he could still hang on to power, diplomats in a closed briefing told AFP.

"Unprecedented levels of horror have been reached. The tragedy does not have an end," Mr Brahimi said amid reports of a shocking new massacre in the Syrian city of Aleppo.

"I'm sorry if I sound like an old broken record," he added. "The country is breaking up before everyone's eyes. Only the international community can help and first and foremost the Security Council."

The government has become more "repressive," the veteran conflict troubleshooter was quoted as saying. But he added that Assad's forces and the opposition were committing "equally atrocious crimes."

Mr Brahimi told the council he was very worried about countries around Syria which face a growing risk of "contamination" from the conflict, which the UN says has left more than 60,000 dead.

"Most regional parties have aligned with one of the parties in Syria," Mr Brahimi said. "There might be implications if the crisis continues spiraling.

The refugee flow is becoming a matter of controversy in these countries." "Syria is becoming a playground for competing forces," he declared.

"None of the neighbors is immune to the fallout consequences of the conflict. The region is facing the risk of contamination," Brahimi told envoys adding that the regional divisions were another reason for UN action.

The Security Council has been paralysed on Syria for more than a year.

Russia and China have vetoed three western-drafted resolutions which would have just threatened sanctions. Brahimi has meanwhile struggled to bring Russia and the United States behind a plan for political transition talks.

Russia accuses the west of seeking simple regime change and insisted that the international community cannot force Assad to stand down. The United States and its allies have backed the opposition stance that there can be no talks with Assad.