More than 14 tons of marijuana was found in a secret drug tunnel running underneath the border between Tijuana and warehouses in an Otay Mesa industrial park, according to Immigration and Customs Enforcement (ICE).
The tunnel, said to be the length of four football fields, runs between two storage buildings officials said.
"Certainly this tunnel here is one of the more sophisticated ones that we've seen in that it took a lot of time to dig they've done some shoring up of it," said Paul Beeson with U.S. Border Patrol.
"They have ventilation electricity going in there extension cords wiring that sort of stuff to get power into it," he added.
ICE agents were led to a warehouse on Kerns St. during a larger investigation. When agents spotted a small cargo truck leaving the warehouse, they alerted California Highway Patrol officers, who pulled it over on northbound State Route 125.
Inside the trailer, officers found about three tons of marijuana packed in boxes.
The driver and a passenger were arrested.
The tunnel reportedly opens up into a backroom of the building.
News crews on scene reported seeing a for-lease sign in front of a warehouse.
Border tunnels are not new to the Tijuana-San Diego region.
On Nov. 2, five people had to be rescued after becoming trapped in a tunnel partly filled with sewage in the 9800 block of Via De La Amistad behind a company called Artic Containers.
Last November, a tunnel that ran 600 yards under the border between Tijuana and San Diego was discovered along with nearly 30 tons of pot.
Later that month another tunnel was discovered. It was equipped with lighting, ventilation, and a rail system for drugs to be carried on a small cart.