A sophisticated border tunnel was discovered connecting San Diego and Tijuana, Mexico, U.S. authorities said, the latest find by investigators who have encountered a number of secret passages in recent years used for drug smuggling.
The passage was recently completed, U.S. Immigration and Customs Enforcement said in a brief statement Wednesday night. A spokeswoman, Lauren Mack, declined to elaborate but said more details would be released Thursday.
Mexican news organizations published photos that show a deep, well-built tunnel near Tijuana's main airport. Alberto Capella, Tijuana's public safety chief, said Wednesday night that a law enforcement operation was underway and he couldn't provide details.
More than 75 tunnels have been discovered along the U.S.-Mexico border since 2008, designed largely to smuggle marijuana to the United States.
The tunnels are concentrated along the border in California and Arizona. San Diego is popular because its clay-like soil is easy to dig. In Nogales, Arizona, smugglers tap into vast underground drainage canals.