Mexican authorities have uncovered a sophisticated underground tunnel stretching nearly 900 feet toward the U.S. border, hidden beneath a residential property in Tijuana.

The tunnel was discovered on Saturday during a raid by Mexican federal agents, supported by the Mexican Navy, in the Nueva Tijuana neighborhood. Officials say the passage runs approximately 869 feet long and lies about 21 feet underground, making it one of the more significant cross-border tunnels found in recent years.

The wood-lined tunnel was located after authorities executed a search warrant at a property in eastern Tijuana. During the operation, agents seized ammunition, cellphones, bank cards, a digital video recorder, and dozens of doses of methamphetamine.

Mexican officials believe the site was being used as a logistical hub for criminal organizations, including the storage and transport of narcotics, weapons, and possibly explosive materials.

U.S. authorities have also been brought into the investigation. Homeland Security Investigations (HSI) confirmed that agents in San Diego are actively involved in probing the cross-border subterranean tunnel near the Otay Mesa area — a major border crossing between Tijuana and San Diego.

“Special Agents with Homeland Security Investigations (HSI) in San Diego… are conducting a criminal enforcement operation involving a cross-border subterranean tunnel in Otay Mesa, CA,” an HSI spokesperson said.

The tunnel’s exact exit point on the U.S. side, how long it had been operational, and whether any arrests have been made have not yet been publicly disclosed.

Cross-border tunnels have long been a preferred method for drug cartels and smuggling organizations to bypass heavy security at official ports of entry.

This latest discovery highlights the ongoing battle against sophisticated smuggling infrastructure along the U.S.-Mexico border. The investigation remains active.