San Diego: US authorities on Wednesday announced the discovery of the longest smuggling tunnel ever found on the southwest border, stretching more than three-quarters of a mile (over a kilometre) from a small industrial building in the Mexican city of Tijuana into the San Diego area.
US Customs and Border Protection said that the tunnel featured an extensive rail/cart system, forced air ventilation, high voltage electrical cables and panels, an elevator at the tunnel entrance, and a complex drainage system.
Following the discovery in August, Mexican law enforcement identified the tunnel entrance and members of the San Diego Tunnel Task Force began mapping the tunnel from Mexico, the agency said.
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The tunnel extends a total of 4,309 feet. (1,313 meters). The next longest tunnel in the US was discovered in San Diego in 2014. It was 2,966 feet (904 meters) long.
The newly discovered tunnel is about 5.5 feet (1.68 meters) tall and two feet (0.61 meters) wide and runs at an average depth of 70 feet (21.3 meters) below the surface, officials said.
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Agents discovered several hundred sandbags blocking the suspected former exit of the tunnel in the Otay Mesa warehouse district within the US.
While there were no arrests, drug seizures or confirmed exit points in the United States, the length, more than 14 football fields, stunned authorities. It went under several warehouses in San Diego's Otay Mesa area, where sophisticated tunnels have typically ended, and extended into open fields.
US authorities said that they are highly confident that the tunnel exited in San Diego at one time, based on its trajectory.
By federal law, US authorities must fill the American side of tunnels with concrete after they are discovered. Officials say that makes it unlikely that the tunnel disclosed on Wednesday had previously been found.
With inputs from AP
