The U.N. Security Council on Saturday unanimously approved a resolution demanding that Syria immediately halt attacks on civilians and allow unfettered humanitarian access to besieged areas and across neighboring borders, threatening unspecified “further steps” if the government does not comply.

The action marked the first time Russia has agreed to a binding resolution against Syrian President Bashar Assad’s regime since the conflict in his country began nearly three years ago. China, which vetoed three previous resolutions along with Russia, joined in approving the measure.

The vote came after lengthy negotiations over the past week. To secure Russia’s agreement, sponsors of the resolution agreed to include specific demands for opposition fighters to cease their own violations of human rights international law, to condemn terrorism and to drop a demand that government violators be referred for prosecution to the International Criminal Court.

Russia had sharply criticized the initial measure. But U.S. officials said they were prepared to push it regardless to force Moscow – currently in the international spotlight during the Sochi Olympics – to take a position on increasingly horrifying reports of human carnage in Syria.

Secretary of State John Kerry said the resolution “could be a hinge-point in the tortured three years of a Syria crisis bereft of hope.” But he said that while it is a resolution of “concrete steps,” they were only first steps and that demanding access means little without full implementation.

The United States and other strong advocates acknowledged a lack of specific enforcement tools in the resolution, which instructs U.N. Secretary General Ban Ki-moon to report back on compliance within 30 days. But U.S. Ambassador Samantha Power and others noted that the threat of “further steps” is far stronger than language in previous, vetoed measures and said it commits the council to take action.

IMPLEMENTATION BEING MULLED

“A resolution is just words,” Power said. “It is implementation that matters, and that’s what we are starting to measure right now.” Language committing the council to further actions, she said, is a “significant hook, a significant commitment by the parties on the Security Council.”

Britain referred specifically to possible future action under articles of the U.N. charter that authorize the use of armed force. Speaking in London, British Foreign Secretary William Hague said that “we will not hesitate to return to the Security Council if the Assad regime fails to meet the demands in this resolution.”

While the resolution includes condemnation of al-Qaida and “affiliated groups” active in Syria, the final version dropped earlier references to Lebanese-based Hezbollah and Iran’s Quds Force, both of which have been involved in the fighting on the government’s side.

In a statement following the vote, Russian Ambassador Vitaly Churkin described the two sides as equally responsible for the situation in Syria and said that genuine opposition forces should “pool efforts with the government” to fight against terrorist involvement.

But the United States and others made clear that they see the resolution as directed primarily at the Assad government. Syria’s humanitarian crisis is not “the inevitable consequence of war,” Power said.