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Proliferation Security Initiative

Proliferation Security Initiative LogoThe Proliferation Security Initiative (PSI) is a global effort to stop the trafficking of Weapons of Mass Destruction (WMD), their delivery systems, and related materials to and from States and non-state actors of concern. Launched by the President of the United States in 2003, U.S. Customs and Border Protection (CBP) began its involvement early in the initiative, when the PSI expanded its activities to include law enforcement cooperation. 

Today, over 100 countries around the globe have joined the PSI by endorsing its “Statement of Interdiction Principles” – a political statement where countries commit to take a variety of actions to halt the illicit trade of WMD and related materials, including:

  • taking specific actions in support of interdiction efforts by land, air and sea;
  • developing procedures to facilitate the exchange of information with other countries; and
  • strengthening national legal authorities to facilitate interdiction.
Two individuals in WMD protective clothing conducting an inspection during an exercise
Demonstration of WMD detection
and identification techniques 

Key Activities for CBP Support to the PSI

CBP participation in the PSI provides the United States Government (USG) with expertise on Customs matters and the full range of CBP enforcement programs, including targeting and analysis, automation tools, technology, detention and inspection, intelligence and information-sharing, industry outreach, as well as methods to halt proliferation networks through post-interdiction activities.  CBP actively supports the PSI through its Operational Experts Group (OEG) meetings, exercises, workshops and other capacity building activities.

CBP maintains a Proliferation Security Initiative Directive, which places its Office of International Affairs (INA) as the primary policy and programmatic lead for CBP contributions to the PSI. The overall INA approach to engagement in the PSI includes: 

  • coordination and consultation with appropriate CBP offices and subject matter experts;
  • engagement in the development of USG policy through coordination with interagency partners;
  • regular participation in international PSI activities; and
  • analysis of where international training, technical assistance and capacity building may be enhanced to include strategic interdiction goals.
Australian Customs participate in PSI Exercise Pacific Sheild
Australian Customs participate
in PSI Exercise Pacific Shield

Notably, since the establishment of the PSI’s Critical Capabilities and Practices (CCP) effort – CBP has been a key international contributor to a number of CCP “tools” and “resources” that can help international partners improve their capacities to meet the PSI Statement of Interdiction Principles.  

Additional Information

CBP is just one entity involved in the global effort to counter the proliferation. CBP works with interagency partners in the United States, as well as international Customs administrations around the globe.

More information on the PSI can be found at:

  • Last Modified: May 21, 2019