News

Deployment of OPCW expert team to Syrian Arab Republic finds chemical weapons previously undeclared to the Organisation

Initial discovery includes chemical munitions, chemical substances, equipment, and relevant documentation

27 May 2026

THE HAGUE, Netherlands—27 May 2026— An expert team of the Organisation for the Prohibition of Chemical Weapons (OPCW) Technical Secretariat, supported by the Syrian authorities, has discovered a significant amount of undeclared chemical weapons, related materials and documentation during its most recent deployment in the Syrian Arab Republic. These findings are being 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, Ambassador 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 operating under the Office of Special Missions (OSM) has been deployed to the Syrian Arab Republic to advance efforts to establish a complete and accurate inventory of the remnants of the Assad-era Syrian chemical weapons programme.  

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.   

According to the OPCW’s monthly update report, the findings include dozens of chemical munitions previously undeclared to the Organisation, 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. 

The full outcome of the deployment will be reported in greater detail at a later stage. 

The team, composed of nine experts from the OPCW Technical Secretariat, is continuing the long-standing work mandated under the Chemical Weapons Convention (CWC), United Nations Security Council Resolution 2118 (2013), and the OPCW Executive Council decision EC-M-33/DEC.1. This work was previously conducted by the Secretariat’s Declaration Assessment Team (DAT) and now by the OSM under whose umbrella the mandates of the DAT – together with those of the Fact-Finding Mission (FFM) and the Investigation and Identification Team (IIT) – have been subsumed.    

The DAT was established in 2014 to engage with relevant Syrian authorities on gaps, inconsistencies, and discrepancies identified by the Technical Secretariat in the Syrian initial declaration of its chemical weapons programme. Following the change of government in Syria in December 2024, the situation in the country has allowed for further mandated activities to take place with a view to clarifying outstanding issues and locate previously undeclared materials. The Technical Secretariat has worked closely with the current Syrian authorities to prepare and conduct this deployment. 

All activities of the Technical Secretariat are being conducted with the effective support of, and in good coordination with, the relevant Syrian authorities. The scale of such a deployment requires extensive cooperation on the ground. Approximately 200 personnel from the Syrian side have contributed to facilitating the mission, including representatives from the newly re-established Syrian National Authority, Ministry of Emergency and Disaster Management, Ministry of Defence, Ministry of Interior, diplomatic security services, intelligence services, medical teams; and chemical, biological, radiological and nuclear (CBRN), explosive ordnance disposal, and demining specialists. 

The Director-General said: “I welcome Syria’s cooperation and support for this deployment. The Syrian authorities now need to declare and destroy what has been found, under the Secretariat’s verification and to continue supporting the Secretariat in unveiling the full scope of the chemical weapons programme they have inherited.” 

The mission’s objective is to support efforts to identify, declare, and ultimately ensure the destruction of any remaining elements of the Syrian chemical weapons programme.  

In addition to continuing the investigations and carrying out deployments to over 100 potential sites, key next steps include the development and implementation of plans for the safe destruction of identified materials, as well as the submission by Syria of a complete and accurate declaration of all remaining chemical weapons-related materials and activities.  

Background   

Syria acceded to the Chemical Weapons Convention (CWC) in 2013 under a stringent verification regime. While Syria submitted an initial declaration of its chemical weapons (CW) programme, the former Syrian government did not declare all its CW programme and attempted – unsuccessfully – to mislead the international community about the overall scope and scale of the Syrian chemical weapons programme. Furthermore, the Technical Secretariat documented and independently confirmed chemical weapons use in Syria both by the former Syrian military forces and by non-state actors, specifically ISIS/ISIL.       

The fall of the Assad government in December 2024 has provided new grounds for the Secretariat to continue its mandated activities towards uncovering the full scope of Syria’s chemical weapons programme and to eliminate it in line with the CWC. In February 2025, the OPCW Director-General visited Syria and held separate meetings with the Syrian President and Foreign Minister. They expressed Syria’s recognition of all OPCW mandates, including the identification of perpetrators of chemical weapons use in Syria and reaffirmed Syria’s full commitment to fulfilling its obligations under the CWC. In March 2025, the Syrian Foreign Minister visited the OPCW and addressed the Executive Council, where he renewed Syria’s commitment to the Convention.         

Since the visit by the Director-General to Damascus in February 2025, the OPCW Technical Secretariat deployed several times to Syria, involving visits to suspected locations, sampling, interviews, collection of documents related to Syria’s chemical weapons programme, and coordination.    

To better coordinate efforts and to provide a foundation for future deployments and potential new mandates, the Director-General created on 1 June 2025 the Office of Special Missions (OSM) in the Technical Secretariat. The work related to the Syrian chemical weapons dossier – verification of declarations and investigation of use of toxic chemicals as weapons – is now coordinated by the OSM. 

Since November 2025, OPCW has re-established a presence in Syria to facilitate upcoming inventory, destruction and verification-related activities.  

As the implementing body for the Chemical Weapons Convention, the OPCW, with its 193 Member States, oversees the global endeavour to permanently eliminate chemical weapons. Since the Convention’s entry into force in 1997, it is the most successful disarmament treaty eliminating an entire class of weapons of mass destruction.  

In 2023, the OPCW verified that all chemical weapons stockpiles declared by the 193 States Parties to the Chemical Weapons Convention since 1997 — totalling 72,304 metric tonnes of chemical agents — have been irreversibly destroyed under the OPCW’s strict verification regime.  

For its extensive efforts in eliminating chemical weapons, the OPCW received the 2013 Nobel Peace Prize.

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