Removing Syria's final known chemical arms has not stamped out fears that the country's deadly gas attacks may continue, Reuters reports.
"There are still some serious issues that need to be addressed and we are not going to stop until those have been addressed," U.S. Secretary of State John Kerry said in Baghdad on Monday. "We remain deeply concerned about reports of systematic use of chlorine gas in opposition areas."
He spoke after a watchdog agency said President Bashar Assad's government had finished placing its declared chemical-warfare stockpile in foreign custody. The regime has blamed opposition forces for any chemical-weapons use in Syria's civil war, but agreed to relinquish its own chemical arsenal after a 2013 sarin-gas strike heightened talk of possible military intervention.
British Foreign Secretary William Hague said the Syrian government's "history of lies and obstruction make it impossible to take its claims at face value, and we support the [Organization for the Prohibition of Chemical Weapons] in its efforts to press Syria for full disclosure."
Sigrid Kaag, the disarmament effort's top international coordinator, said her mission would push to resolve questions over the regime's declarations by September, the New York Times reported on Monday.
Meanwhile, Russia echoed warnings by its Damascus ally that Syrian rebels may launch new chemical strikes, ITAR-Tass reported.
"We are still concerned about the ability of different terrorist groups to obtain chemicals that could be used for hostile purposes," Russian Ambassador to the United Nations Vitaly Churkin said on Monday.
A specially equipped U.S. vessel is expected next week to take custody of Assad's deadliest declared warfare chemicals, Reuters reported. The ship would then neutralize the materials in a process that may take up to two months.