U.N.-Arab League mediator Lakhdar Brahimi appealed to the 15-nation U.N Security Council to overcome its deadlock and take action to help put an end to the Syrian civil war.
However, it was not clear whether his latest report, which diplomats said was his bleakest since his appointment last year, would persuade Russia to agree to support concrete U.N. steps to try to halt the bloodshed.
"The country is breaking up before everyone's eyes," Brahimi was quoted as saying by diplomats inside the closed-door meeting. "Only the international community can help and first (and) foremost the Security Council."
"I told the council that I'm embarrassed to be repeating the same thing," Brahimi told reporters after the meeting. "Syria is being destroyed, bit by bit."
He said the principles of a political transition in Syria, agreed to at talks among major world and regional powers in Geneva in June last year, could form the basis for a Security Council plan of action.
"In the Geneva communique the meaning of full executive powers (for a transitional government) must be clarified, but it clearly means that Assad should have no role in the transition," one diplomat quoted Brahimi as saying.
The mediator told the council that Assad may be able to hold onto power for the time being, but that "the Syrian regime's legitimacy has been seriously, probably irreparably, damaged."
'BRAHIMI IS 'NOT A QUITTER
Brahimi played down rumors that he was planning to resign, though he added that it was not a job he had wanted.
"I'm not a quitter," he said. "The United Nations has no choice but to remain engaged with this problem, whether I'm there or not. The moment I feel that I am totally useless I will not stay one minute more."
Western diplomats said Russia is more concerned with countering U.S. influence in the Middle East and maintaining some level of Russian leverage in the region than it is with protecting Assad.
"There's no obvious way forward," U.S. Ambassador to the United Nations Susan Rice told reporters after the meeting. "I don't have any promises of any big breakthrough."
Brahimi added "unprecedented levels of horror" have been reached in Syria, and that both the government and the opposition forces have committed atrocious crimes.
Highlighting his point about atrocities, opposition activists said at least 65 people had been found shot dead with their hands bound in the northern Syrian city of Aleppo on Tuesday in what they called a "new massacre."
The United Nations is not present in all parts of Syria but it is maintaining limited aid operations. It has warned, however, that it needs more money and better access on the ground.
Brahimi told Security Council members that the regional outlook was also worrying.
"Syrian factions are getting cross-border support from neighboring countries," a diplomat quoted Brahimi as saying. "Syria is becoming a playground for competing forces. None of the neighbors are immune to the fallout consequences of the conflict."