MEXICO CITY - A total of 36.4 tons of marijuana were seized in the "most sophisticated tunnel on the border" between Mexico and the United States, local media reported Thursday.

Among them, 32.4 tons were seized on the US side, and 4 tons in Mexico. Authorities said no one knew who owned the drug with a value of nearly $65 million. Six people were arrested in the operation.

Derek Benner, a special agent of the Immigration and Customs Enforcement (ICE), told reporters in San Diego that the 600-meter-long passage, located between Tijuana and San Diego, was equipped with a hydraulic elevator, electric wagons running on rails, a wooden staircase and hardwood floors from one end to another.

"This is an incredibly efficient tunnel designed to move a lot of narcotics," he said, believing that the tunnel began operations recently.

Lauren Mack, an ICE spokeswoman, described the tunnel as one of the "most sophisticated" ever discovered on the border.

This is the second largest tunnel found in November on the US-Mexico border, and the seventh in the last five years.