GENEVA, Sept 13 (Reuters) - The United States and Russia, in talks to eliminate Syria's chemical weapons program, are "coming to agreement" on the size of its toxic stockpiles, a U.S. official said on Friday.
The talks in Geneva between teams led by U.S. Secretary of State John Kerry and Russian Foreign Minister Sergei Lavrov, which began on Thursday, are at a "pivotal point" and are continuing into Saturday, the official told reporters.
Kerry and Lavrov are meeting in an attempt to reach agreement on details of a plan offered by Russia this week under which Syria would give up its chemical weapons stockpiles, believed to be among the world's largest.
A key first step is to determine the extent of Syria's stocks as a prelude to inspecting, securing and ultimately destroying them.
Kerry said in congressional testimony earlier this week that Washington assesses that Syria has about 1,000 tons of chemical agents. Russia's estimate reportedly has been significantly smaller.
The two sides "made progress in coming closer to agreement on the size of the chemical weapons stockpile," said the U.S. official, who briefed reporters on condition of anonymity and declined to provide further details.
In Washington, senior Obama administration officials said the United States does not expect a U.N. Security Council resolution on Syria's chemical weapons to include a potential use of military force because Russia would veto it.
In Geneva, Russian and U.S. experts were discussing other details of what would be a complex, and likely risky, mission to neutralize Syria's chemical weapons in the middle of it's 2-1/2-year civil war.
Among them was how to provide security for any weapons inspectors who would go to Syria, the official said.
Overall, the talks, which continued late into the night on Friday, were at a "pivotal point," the official said.