The Trump administration moved Monday to expand a U.S. Customs and Border Protection surveillance system used to detect cartel-dug tunnels along the southwest border, releasing a solicitation for a contract with a ceiling of $100 million, officials said.
The Department of Homeland Security solicitation targets an expansion of the Persistent Surveillance and Detection System, or PDS, to strengthen detection in high-risk border sectors. The effort follows two major tunnel discoveries this year that officials say illustrate risks to border security and public safety, and it is part of broader work covered in our Border Coverage.
Background
DHS released the solicitation for what it calls the Cross Border Tunnel Threat program, seeking a contract worth up to $100 million, according to agency documents. The procurement anticipates an award in the first quarter of fiscal 2026, with work to be completed by Dec. 31, 2026, according to the notice.
Officials describe the PDS as a layered monitoring capability that combines persistent aerial or ground sensors with analytics to detect anomalous activity consistent with tunnel construction and subsurface movement. Border Patrol agents use PDS outputs to estimate where an underground passage likely crosses the international boundary and to forecast a tunnel’s probable subsurface trajectory into U.S. territory, the agency said.
DHS said the planned expansion will prioritize sites in California and other southwest border locations where intelligence indicates elevated tunnel activity. The procurement notice lays out technical requirements for continuous monitoring, data analysis, and integration with existing law enforcement systems.
Recent Tunnel Discoveries
Two significant tunnel finds this year prompted heightened attention from federal and local agencies.
- San Diego discovery: In April, Border Patrol agents in the San Diego sector discovered and disabled a large narcotics tunnel linking Tijuana to the Otay Mesa area, officials said. The passage measured nearly 3,000 feet, was about 42 inches high and 28 inches wide, and reached roughly 50 feet below the surface at its deepest point. The tunnel extended more than 1,000 feet inside the U.S. and was equipped with wiring, lighting, ventilation and a track system for moving contraband, records show.
- El Paso discovery: In January, agents in the El Paso sector uncovered a man-made tunnel running from Ciudad Juárez into a public storm drain in El Paso. That tunnel was braced with wood, measured about 6 feet high and 4 feet wide, and included lighting and ventilation, officials said.
In the San Diego case, U.S. and Mexican authorities worked together to identify an entrance inside a residence in the Nueva Tijuana neighborhood, and Mexican officials served a warrant at that location, according to agency records. Border Patrol officials say organized criminal groups, including the Sinaloa Cartel, have long used underground routes in parts of southern California.
Border Patrol records show agents have located more than 95 tunnels in the San Diego area since 1993 and have destroyed many by backfilling or otherwise remediating the passages. Federal officials have repeatedly warned that tunnels can present hazards to agents and residents and can facilitate large-scale smuggling of drugs, weapons and people.
Operational and Interagency Details
Officials say expanding the PDS is intended to improve law enforcement ability to locate tunnel trajectories and probable crossing points beneath the border, bolstering efforts to disrupt smuggling networks and reduce threats to public safety. The program would be managed by U.S. Customs and Border Protection and used by Border Patrol agents in coordination with federal investigative agencies.
FBI and Border Patrol officials in El Paso and other sectors have cautioned that tunnels pose risks beyond smuggling, including the potential for violent encounters, criminal facilitation within smuggling corridors, and hazards associated with subterranean work. Those agencies emphasized the need for coordinated investigations, evidence preservation, and careful remediation to protect residents and personnel.
CBP San Diego Sector acting Chief Patrol Agent Jeffrey Stalnaker said agents faced hazardous conditions while investigating the San Diego tunnel and stressed the operational risks involved in subterranean searches. El Paso Sector Chief Patrol Agent Anthony Scott Good said agents remain vigilant and that U.S. and Mexican partners cooperated to remediate the discovered tunnel. FBI El Paso special agent in charge John Morales highlighted the importance of federal, state and international coordination to counter border threats.
Border Patrol has asked the public to report suspicious activity and provided anonymous reporting options, including a toll-free tip line and WhatsApp number for El Paso and a local tip line for San Diego.
- El Paso: call 1-800-635-2509 or WhatsApp (915) 314-8194
- San Diego: call 619-498-9900
Budget, Procurement and Oversight
A contract ceiling of $100 million represents a sizable, short-term federal investment in surveillance technology. The procurement timeline and technical specifications in the solicitation will shape how quickly additional sensors and analytic capabilities can be deployed. Implementation will require coordination across DHS components, interagency partners and Mexican authorities to act on detections and to conduct follow-up investigations.
Congressional committees with jurisdiction over homeland security and appropriations may scrutinize the program’s effectiveness, cost per sector monitored, and safeguards for privacy and civil liberties. Agencies typically must balance rapid deployment of capabilities with requirements for testing, training and legal compliance when expanding monitoring programs at the border.
Analysis
Expanding PDS targets a specific enforcement gap: subterranean routes that bypass surface barriers and checkpoints. Improved detection could disrupt large-scale smuggling operations and reduce the volume of contraband and human trafficking moving through underground passages, strengthening border integrity and public safety.
There are tradeoffs. A $100 million contract is a significant federal outlay that will be weighed against other homeland security priorities. The effectiveness of expanded surveillance will hinge on timely intelligence sharing, operational coordination with Mexican authorities, and the ability of law enforcement to act on detections without creating unintended safety risks for agents or residents.
The tunnel discoveries also raise governance questions about long-term prevention. Detection and interdiction blunt current operations, but officials will face pressure to pair those tactics with criminal investigations into financing, construction networks and local facilitation to reduce recidivism. Debates are likely to focus on balancing investments in technological surveillance, strengthening bilateral enforcement cooperation, and addressing the criminal economies that drive tunnel construction.
