The Proliferation Security Initiative (PSI) Balkans Regional Engagement, co-hosted by the United States and Slovenia from April 14-16, 2025, took place in Ljubljana, Slovenia. This multilateral exercise gathered 62 leaders from various sectors in 18 countries, including the United States, Slovenia, and others from the region. The primary aim was to enhance efforts in countering the proliferation of weapons of mass destruction (WMD), improving export control, and implementing sanctions effectively.
Attendees exchanged information about current proliferation pathways of WMD, related delivery systems, and materials. The event provided an opportunity to learn from real-world counterproliferation case studies and to pinpoint legal framework gaps that could impede successful interdiction of related cargo. Through expert briefings, participants gained a better understanding of the risks, red flags, and potential of sensitive item diversions, proliferation financing, sanctions evasion, and the role of emerging technologies in WMD and missile programs.
A tabletop exercise allowed participants to refine their interdiction skills through various complex scenarios. These activities necessitated coordinated actions both within countries and across borders, employing national legal authorities, catch-all controls, and ship boarding agreements.
The PSI, begun in 2003, aims to prevent the transfer of WMD, their delivery systems, and related materials to state and non-state actors. To date, 116 states have supported the PSI Statement of Interdiction Principles.