UNITED NATIONS — The U.N. Security Council voted unanimously Friday night to secure and destroy Syria’s chemical weapons stockpile, a landmark decision aimed at taking poison gas off the battlefield in the escalating 2½-year conflict.

The vote after two weeks of intense negotiations marked a major breakthrough in the paralysis that has gripped the council since the Syrian uprising began. Russia and China previously vetoed three Western-backed resolutions pressuring President Bashar Assad’s regime to end the violence.

“Today’s historic resolution is the first hopeful news on Syria in a long time,” U.N. Secretary-General Ban Ki-moon told the council immediately after the vote.

For the first time, the council endorsed the roadmap for a political transition in Syria adopted by key nations in June 2012 and called for an international conference to be convened “as soon as possible” to implement it.

Ban said the target date for a new peace conference in Geneva is mid-November.

The resolution calls for consequences if Syria fails to comply, but those will depend on the council passing another resolution in the event of non-compliance. That will give Assad ally Russia the means to stop any punishment from being imposed.

The vote came just hours after the world’s chemical weapons watchdog adopted a U.S.-Russian plan that lays out benchmarks and timelines for cataloguing, quarantining and destroying Syria’s chemical weapons.