Syrian opposition groups have roundly rejected the plan, calling it ambiguous and a waste of time and vowing not to negotiate with Assad or members of his "murderous" regime.
Elaraby, who has held private meetings with Syrian opposition figures at the League's headquarters in the past, said the agreement did not meet Arab expectations because it did not specify a time frame for a "clear transition" as the League had called for.
The U.S. backed away from insisting that the plan should explicitly call for Assad to have no role in a new Syrian government, hoping the concession would encourage Russia to put greater pressure on its longtime ally to end the regime's violent crackdown.
The conflict has killed more than 14,000 people since the revolt began in March 2011, according to opposition estimates. The fighting has grown increasingly militarized in recent months, with rebel forces launching attacks and ambushes on regime targets.
Assad has refused to budge, saying his country is at war with terrorists — the term he uses for his armed opponents. On Monday, he ratified a new terrorism law that includes a clause specifically aimed at the opposition. Under the law, the penalty for terrorism that aims to change the regime would exceed 20 years of hard labor.
As the conflict drags on, concerns are mounting that the violence will spiral outside the country's borders. Tensions already are running high between Damascus and its northern neighbor, Turkey, after Syria shot down a Turkish military plane on June 22.
Syria said the jet violated its airspace, but Turkey says the aircraft was shot down over international waters.
Turkey responded by setting up anti-aircraft guns along the frontier and said Monday it dispatched fighter jets to its border after Syrian helicopters flew too close to the frontier for a second day on Sunday.
In Brussels on Monday, Fogh Rasmussen said the Syrian regime "has lost all humanity and all legitimacy." But there is little appetite for the type of military intervention that helped topple Libya's Gadhafi, in part because there is no real opposition to get behind.
The international community is also hesitant to get involved in another country in turmoil.
"Every member of the international community should use its influence and spare no effort to bring an end to the bloodshed and move Syria forward," he said. "This conflict has already gone on for too long. It has cost too many lives, and put the stability of the whole region at risk."
Kennedy reported from Beirut.
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