Closure of US-Mexico Drug Smuggling Tunnel a Sign That Terrorists are Going Underground, Warns Border Patrol Chief

US border patrol agents have uncovered and dismantled a sophisticated underground tunnel stretching from Tijuana, Mexico to San Diego, California—a secret passage used for large-scale drug smuggling. The US Customs and Border Protection (CBP) described the tunnel as a potential tool not only for drug traffickers but also for terrorist groups, sparking renewed national security concerns.

The uncompleted tunnel, which extended more than 1,000 feet into US territory, was detected in April and successfully sealed on Wednesday 18 June 2025, according to an official CBP statement. Authorities say the discovery highlights a growing shift in how criminal and potentially terrorist organisations attempt to exploit underground routes to bypass heavily monitored borders.

What Did Border Patrol Find?

Following a tip-off and subsequent investigation, the CBP Tunnel Team entered the underground passage, which measured 2,918 feet (890 metres) in total length and reached a depth of nearly 50 feet. While navigating the tunnel, agents encountered makeshift barricades apparently designed to delay detection.

'The uncompleted tunnel extended more than 1,000 feet inside the US and was highly sophisticated,' CBP confirmed in a press release.

Despite being unfinished, the tunnel was already equipped with electrical wiring, lighting, a ventilation system, and even a rail track—indicative of its intended use for smuggling large volumes of illegal drugs.

Border patrol agents traced the tunnel's origin to the Nueva Tijuana neighbourhood in Mexico. The exit point, meanwhile, was located within a commercial warehouse in San Diego.

A Warning Sign of Underground Terror Threats?

San Diego Sector Acting Chief Patrol Agent Jeffrey D. Stalnaker raised alarms over the tunnel's complexity and potential misuse by foreign terror groups.

'As we continue to strengthen the nation's air and maritime border security, it's not surprising that foreign terrorist organisations would resort to underground routes,' he told Fox News.

Stalnaker added: 'Disruption of narcotics smuggling tunnels is critical to protecting American lives.'

What Happens Next?

To permanently block access and prevent future use, the CBP will fill the tunnel with thousands of gallons of cement. The move is part of a broader security strategy in the region, where nearly 100 tunnels have been discovered and disabled in the San Diego area since 1993.

CBP stressed that national safety remains its top priority: 'To prevent the illicit smuggling of humans, drugs, and other contraband, the US Border Patrol maintains a high level of vigilance along corridors of egress away from our nation's borders.'

The successful shutdown of the tunnel underscores growing concerns among US officials that criminal enterprises and terror cells may increasingly exploit underground routes as above-ground surveillance tightens.

As authorities continue to investigate the origins and intended use of the tunnel, CBP officials reaffirmed their commitment to securing the US-Mexico border against all forms of illicit activity.