UNITED NATIONS (AP) — The head of the mission charged with destroying Syria’s chemical weapons said Thursday the last 16 containers of dangerous chemical agents that need to be transported out of the country are in a contested area not far from Damascus that is currently inaccessible.

Sigrid Kaag appealed to countries with influence on armed groups fighting in Syria to help arrange unfettered access for experts to the site at a military air base and safe transport for the chemicals to the port of Latakia, where Danish and Norwegian ships are waiting to take the containers to a U.S. vessel for destruction.