The debate surrounding a chemical attack in Syria last month shifted Monday to a proposal for the Assad regime to surrender its chemical weapons arsenal to avoid a U.S. military strike – but little has been said about its alleged possession of even-deadlier biological weapons.

Syria has been suspected for decades of having an undeclared biological warfare (BW) program, although whether this includes actual stockpiles of munitions is unclear.

Syria signed the 1972 Biological and Toxin Weapons Convention (BWC), but has never ratified it.