The five permanent members of the UN Security Council have agreed on a draft UN Security Council resolution aimed at eliminating Syria's chemical weapons.
Samantha Power, the U.S. ambassador to the United Nations, said a deal was struck with Russia "legally obligating" Syria to give up its chemical stockpile.
Also on September 26, Russian Foreign Minister Sergei Lavrov said an "understanding" had been hammered out.
A U.S. State Department official hailed the deal as a "breakthrough."
The United States and Russia had been at odds over how to enforce it, dragging out negotiations.
According to news agencies, the draft does not include any direct trigger for sanctions or military action under Chapter VII of the UN Charter if Damascus fails to comply with a U.S.-Russian-brokered deal to put its chemical weapons under international control.
Such action would reportedly require another Security Council resolution.
A vote on the draft at the Security Council could come as early as late on September 27.
Syria agreed to give up its chemical weapons following U.S. threats of possible military action over a sarin-gas attack on civilians in the suburbs of Damascus last month that Washington says killed 1,400 and blamed on the regime of Bashar al-Assad.
British Ambassador Mark Lyall Grant said he was pleased the draft resolution called for "accountability" for those responsible for the chemical attacks, although he added he would have liked a direct reference to the International Criminal Court in The Hague -- something diplomats said Russia opposed.
Diplomats from the permanent Security Council members -- China, Russia, the United States, France, and Britain -- had been haggling over the details of a resolution to back the U.S.-Russian accord announced on September 14 in Geneva to eliminate Syria's chemical weapons.
On September 26, Russian Deputy Foreign Minister Sergei Ryabkov said that his country was ready to help guard Syrian chemical-weapons sites and destroy Assad's stockpiles but would not ship any of the chemical arms to Russia for destruction.
With reporting by AP and Reuters