United States Invests Millions to Detect Border Smuggling Tunnels

The United States is allocating US$100 million to expand the Persistent Surveillance and Detection System, a program intended to identify tunnels used by criminal groups along high-risk segments of the border shared with Mexico. The measure follows recent discoveries of underground structures used for the movement of drugs, weapons, and people.

According to the US Department of Homeland Security (DHS), the investment aims to “strengthen continuous detection capabilities with precise geolocation of cross-border tunnels,” enabling authorities to identify completed structures and those that are under construction.

The DHS and the Federal Bureau of Investigation (FBI) have reported an increase in tunnel-related activity in areas considered strategically sensitive. The FBI says that Tijuana is the location with the highest number of secured tunnels along the border. The agency has also documented similar findings in Sonora, Chihuahua, and Tamaulipas.

These findings reflect a sustained operational pattern by criminal organizations with the logistical capacity to build reinforced, ventilated, and electrically wired underground passages. The FBI reports that over 95 tunnels have been detected in the San Diego area since the early 1990s. Tunnel-based smuggling remains a long-standing challenge for authorities, which face structures that have evolved in size, depth, and internal complexity.

The investment will fund the acquisition of three core technologies: ground-penetrating radar, laser-based coating scanners, and acoustic sensors designed to analyze subterranean patterns. These tools form part of an international procurement process open to companies from at least 25 countries, including Mexico, according to the DHS.

Ground-penetrating radar will support subsoil imaging to detect anomalies consistent with human-made excavations. Laser scanners will examine structural coatings to determine whether modifications correspond to tunnel construction. Acoustic sensors will identify low-frequency vibrations associated with excavation activity or underground movement. Together, these tools will form a monitoring network designed to maintain persistent surveillance and reduce detection times.

The DHS referenced two recent tunnel discoveries as part of the justification for the procurement. The first was identified in January 2025 between Ciudad Juarez and El Paso. The structure was under construction, reinforced with wood, and equipped with lighting and ventilation. According to the agency, it measured nearly 2m in height and more than 1m in width, and it connected Ciudad Juarez with a drainage system in El Paso.

The second tunnel was located in April between Tijuana and San Diego. It extended 914m, with a height of 1.07 meters and a width of 71cm. It was located at a depth of 15m and included electrical wiring, ventilation, lighting, and internal tracks for transporting goods. The structure contained improvised barricades intended to slow enforcement activity.

The White House says that US President Donald Trump is evaluating additional actions to address cross-border criminal activity. The administration acknowledged recent cooperation with Mexican authorities and referenced actions taken by the federal administration of Mexico in relation to drug-control policy. 

The United States Department of Homeland Security expects procurement and initial deployment phases to begin once the bidding process concludes. The agency anticipates that the incorporation of new technologies will provide more precise geolocation and expand coverage in zones where recent tunnel activity has been documented.