Secretary of State Hillary Clinton, facing resistance from Russia, appealed to the United Nations Tuesday to support an Arab League-backed resolution that calls for Syrian President Bashar Assad to step down. 

In a forceful plea at a meeting of the U.N. Security Council, Clinton voiced confidence in the prospects for a political transition in Syria. But she suggested the death toll would rise considerably if the international community does not apply more pressure soon. 

"We all know that change is coming to Syria. Despite its ruthless tactics, the Assad regime's reign of terror will end and the people of Syria will have a chance to chart their own destiny," she said. "The question for us is how many more innocent civilians will die before this country is able to move forward." 

Clinton said nations have a choice -- "stand with the people of Syria and the region or become complicit to the continuing violence there." 

More than 5,000 people have died since the Syrian uprising began last March, nearly 100 on Monday alone. Clinton said "the evidence is clear that Assad's forces are initiating nearly all of the attacks that kill civilians," though she warned violence could "spiral out of control" as more Syrians take up arms. She warned about a possible "descent into civil war."