The U.S.-Mexico border has essentially been porous for most of the last three years. Because of the prolonged and public nature of this border insecurity, foreign criminals, intelligence officers/agents, and terrorists have had the time, incentive, and means to infiltrate the United States.

In 2024, the FBI’s key border concern has focused on the Central Asian ISIS-K syndicate of the Islamic State terrorist organization. The U.S. military withdrawal from Afghanistan has afforded that group a relatively safe haven free of effective U.S. intelligence, detection, and interdiction. ISIS-K has been involved in several major attacks, especially the March 2024 slaughter of nearly 150 civilians at a Moscow-area concert hall. Many of those involved in that attack were Tajik nationals. And while a number of other international ISIS-K attack plots have been disrupted, ISIS-K fighters practice generally impressive operational security to avoid detection. Consider, for example, that where U.S. intelligence provided to Russia in advance of the concert hall attack successfully highlighted the attack’s theme, it was limited in terms of specifying suspects and the specific target.