But Russian officials have stressed repeatedly that all decisions on Syria’s future would be taken by Syrians alone, and they have declined to say what steps they would take to implement the accord. U.S. officials have expressed concern that Russian President Vladimir Putin is not using the leverage Russia has built up with its longtime ally to help bring about Assad’s ouster.

“I don’t think Russia and China believe they are paying any price at all – nothing at all – for standing up on behalf of the Assad regime,” Clinton said. “The only way that will change is if every nation represented here directly and urgently makes it clear that Russia and China will pay a price, because they are holding up progress – blockading it. That is no longer tolerable.”

The second major development of the past week was a conference in Cairo, sponsored by the Arab League and attended by 210 members of the anti-Assad resistance, which endorsed the outline of a bill of rights for a future elected government, as well as a timetable for free elections and drafting a constitution.

The Cairo meeting got relatively little international attention, for it was overshadowed by public disputes among the fractious opposition, and the documents themselves were in some cases “execrably translated,” said a U.S. official, who wasn’t authorized to speak publicly about the meeting.

But a State Department official in Washington said the Cairo accords constituted an important advance. “It’s a huge step forward,” said the official, who also wasn’t authorized to speak about it. “It’s very similar in its detail to what the (Libyan National Transitional Council) put out when it was in the same position,” in 2011.