Russia and China will regret a weekend vote in the UN Security Council that would have condemned Syria for its brutal crackdown on protesters, Washington's UN ambassador Susan Rice said on Monday.
"Russia and China will, I think, come to regret this decision which has aligned them with a dying dictator, whose days are numbered, and put them at odds with the Syrian people and the entire region," Rice told CNN television.
She added that the vote on Saturday, which came just hours after Syrian forces bombed the city of Homs, killing hundreds of civilians, "put a stake in the heart of efforts to resolve this conflict peacefully."
The resolution on the table "would have given political backing to an Arab League plan to begin a negotiated transition," Rice said.
The measure, she said, "would have done nothing more than have encouraged the Arab League in their efforts to bring the two sides to the negotiating settlement and transition to democracy."
China and Russia "have, by their actions, by their veto, dramatically increased the risk of greater violence and we've seen the manifestations of that and indeed increase the risk of civil conflict," the UN envoy said.
Her strong words echoed remarks by US Secretary of State Hillary Clinton after the council vote, who called it a "travesty."
"Those countries that refused to support the Arab League plan bear full responsibility for protecting the regime in Damascus," Clinton said on Saturday, the heaviest reported day of death since the Syrian uprising began.
US President Barack Obama on Saturday accused Syrian President Bashar al-Assad's government of murdering civilians in an "unspeakable assault" in Homs, and demanded that Assad step down.
"Assad must halt his campaign of killing and crimes against his own people now. He must step aside and allow a democratic transition to proceed immediately," Obama said in a statement.
Rice vowed on Monday that the international effort to reach a common stand on the Syria crisis would go forward.
"The United Nations will continue on this issue," she said.
"Thirteen of the 15 members of the Security Council are united in seeking a peaceful resolution of this. We will step up our economic pressure. We'll coordinate with our Arab partners... to increase the pressure on Assad and isolate him.