Federal officials have uncovered a massive, cross-border tunnel used to transport drugs that stretched from the suburbs of San Diego to a home in Tijuana, Mexico.

As part of the sting operation, seven tons of marijuana and a ton of cocaine were seized in a raid coordinated by agents from various federal bureaus.

"We believe this to be the longest tunnel that we have discovered in this district to date," said Laura Duffy, U.S. attorney for the Southern District of California.

Arrests & Value

Six people were arrested as part of the sting, which authorities noted was further highlighted by the 2,000 pound cocaine seizure. The drugs have an estimated value of $22 million and charges against those taken into custody include conspiracy to import and distribute cocaine.

Tunnel Spot Equipped With Rail System, Motorized Freight Elevator

Reports are the tunnel stretched roughly three feet in width and measured around a half-mile in length. The spot where it was dug was also equipped with lights, ventilation, a rail system and a motorized freight elevator large enough to transport at least 10 people.

Authorities stressed there have now been more than a dozen secret passages uncovered along the California border over the last decade. In addition, over the last five years agents have uncovered more than 75 cross-border tunnels used for drug smuggling, many of them in the vicinity of California and Arizona border.

Agents recently discovered a 416-yard tunnel that ran from a home in the South California desert across the Mexico border to a small business.

In that instance, Duffy noted that the hole in the floor was covered by tile and led to a shaft that descended underground.

"We repeatedly see cartels trying to build these tunnels, they spend years doing it, they spend millions of dollars doing it, to create their own private underworld of secret passageways to move drugs unchecked into this country," Duffy said. "But for the builders, for the financiers, for the operators of these passageways, there's no light at the end of these tunnels."

At least four people were arrested as part of that sting, which also ended with the seizure of more than 1,350 pounds of marijuana valued at upwards of $6 million.