U.S. officials said technical experts and intelligence analysts were comparing the data to U.S. intelligence collected from satellites and other sources.

“We were surprised the declaration was as complete as it was. But we do not believe [they] identified all the sites and that did not surprise us,” said a senior U.S. official briefed on Syria’s initial declaration.

The OPCW’s disarmament schedule, reached early Saturday in The Hague, calls for Syria to submit a more detailed inventory within seven days. It must file a still more comprehensive document within 30 days, including elements such as a specific plan for destroying its chemical arsenal.