Syria has expanded its chemical weapons arsenal in recent years with help from Iran and by using front organizations to buy sophisticated equipment it claimed was for civilian programs, according to documents and interviews.

The buildup has taken place despite attempts by the United States and other Western countries to block the sale of precursor chemicals and so-called dual-use technology to Damascus, according to the documents. …

A 2006 cable recounts a confidential presentation by German officials to the Australia Group, an informal forum for 40 nations plus the European Commission that protects against the spread of chemical weapons. The cable described Syria’s cooperation with Iran on Syria’s development of new chemical weapons, noting that Syria was building up to five new sites producing precursors to chemical weapons.