U.S. Border Patrol agents recently discovered and disabled a nearly 3,000-foot-long narcotics smuggling tunnel sitting beneath the US-Mexico border.

Agents found the tunnel — which linked Tijuana and San Diego — in early April while it was actively under construction. 

Beneath a section of the Otay Mesa Port of Entry, an underground passageway was discovered with a planned exit location near or within a commercial warehouse area in San Diego, as reported by U.S. Customs and Border Protection.

As officials entered the “highly sophisticated” tunnel, they encountered barricades that appeared to be strategically placed to block law enforcement from accessing its entrance, according to the announcement.

U.S. Customs and Border Protection stated that thousands of gallons of concrete will soon be poured into the tunnel to prevent its use by Foreign Terrorist Organizations.

Traffic backs up the San Ysidro Southbound Inspection as people enter Tijuana, Mexico at the Otay Mesa Port of Entry on May 3, 2025, in San Diego, California.  (Kevin Carter/Getty Images)

“As we continue to strengthen the nation’s air and maritime border security, it’s not surprising that foreign terrorist organizations would resort to underground routes,” Jeffrey D. Stalnaker, acting chief patrol agent of the San Diego Sector, said in a statement. “Disruption of narcotics smuggling tunnels is critical to protecting American lives.”

More than 95 tunnels have been decommissioned in the San Diego area since 1993. 

U.S. Customs and Border Protection did not immediately respond to Fox News Digital’s request for comment.