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Overview: Profiles of Individual Radicalization in the United States-Foreign Fighters (PIRUS-FF)

NCJ Number
Date Published
4 pages

Based on an analysis of data in the database Profiles of Individual Radicalization in the United States – Foreign Fighters (PIRUS-FF), this report  develops a profile of “foreign fighters.” i.e., U.S. residents “who have been publicly identified in open sources as having left, attempted to leave, or expressed an interest in leaving the United States for the purpose of supporting the activities or interests of a foreign non-state armed group or foreign regime, and were motivated by religion, ethnicity, or other ideology.”



The PIRUS-FF data indicate that U.S. foreign fighters have been associated with 33 foreign militant groups across 14 unique conflicts since 1980. Over a period of a few years, individuals traveling to join the Islamic State of Iraq and the Levant (ISIL) have composed 23 percent of the database, compared to 17 percent for al-Qaeda core and 14 percent for al-Shabaab. A significant number of foreign fighters have also sought to join the Taliban in Afghanistan, mostly with the intent of engaging in combat against U.S. forces. Profile differences are noted by commitment to various terrorist groups. This report also provides information on foreign fighters’ radicalization while living in the United States through internet use, the duration of radicalization, plots to launch attacks in the United States, weapons/tactics training, and financial and weapons support. 13 figures