OPCW experts find undeclared chemical stockpiles in Syria, 18 arrested

A team of experts from the Organisation for the Prohibition of Chemical Weapons (OPCW) Technical Secretariat, supported by Syrian authorities, has discovered a significant amount of undeclared chemical weapons, related materials and documentation during its most recent deployment in Syria. 

The findings of the team were made public in the context of the monthly update report on Syria, issued by the OPCW Technical Secretariat on 26 May 2026. 

OPCW director-general, Fernando Arias, said: "The outcome of this deployment is significant. It confirms the Secretariat’s repeated assessment since 2014 that the former Syrian regime withheld information and unsuccessfully attempted to mislead the Secretariat and the international community on the extent of its chemical weapons programme."

Since early May, an expert team of the OPCW Technical Secretariat has been deployed to Syria to advance efforts to establish a complete and accurate inventory of the remnants of the Assad-era Syrian chemical weapons programme, according to the OPCW.  

Out of more than 100 locations across Syria considered as potentially relevant to the chemical weapons programme, the Technical Secretariat prioritised a subset of high-interest sites based on information collected, analysed and corroborated over the past 12 years. 

The current deployment focused on a group of sites located in northern coastal and central areas of the country, broadly within a geographic triangle encompassing Hama, Homs and Latakia. These areas are known to have remained a stronghold of the former regime throughout the 13-year-long conflict in Syria.   

The findings include dozens of chemical munitions previously undeclared to the OPCW, including the same type of aerial bombs that were used in chemical attacks in Ltamenah in March 2017 and Khan Shaykhun in April 2017. Rockets were also found, of the same type as those that were used in the Ghouta chemical weapons attack in August 2013. 

The findings also include quantities of separately stored chemicals and related equipment, the nature of which is currently under technical analysis; and thousands of pages of documentation relevant to the Syrian chemical weapons programme recovered at multiple sites. 

Syria’s permanent representative to the OPCW, Mohamed Katoub, announced that authorities had detained 18 individuals suspected of involvement in operating and managing the former regime’s chemical weapons programme. According to Katoub, those detained include senior military, political and technical officials, although their identities and specific roles have not been disclosed.