Cross-border drug tunnel in San Diego is equipped with rail system, 8 tons of marijuana seized

U.S. authorities say a tunnel designed to smuggle drugs from Tijuana, Mexico, to San Diego is equipped with electricity, ventilation and a rail system.

U.S. immigration and Customs Enforcement said Thursday that authorities seized more than 8 tons of marijuana and 325 pounds of cocaine in connection with the discovery. Three suspects are in custody.

The tunnel links warehouses in Tijuana and San Diego's Otay Mesa industrial area.

More than 75 drug tunnels have been found on the U.S.-Mexico border since 2008, many of them crudely built and incomplete. They are concentrated in California and Arizona.