The authorities of San Diego, California, have discovered a secret drug tunnel running from Mexico with seven tons of marijuana and more than a ton of cocaine, RIA Novosti reported with a reference to Fox News.

According to the channel, the tunnel extends almost 300 meters from one of the houses in Tijuana in the north-west of Mexico to the US border. It’s lengths on the American territory makes approximately 500 meters. Local authorities say that it is the longest drug tunnel that has ever been found in California.

The tunnel was used for drug storage and was equipped with rails, ventilation, electricity, and a large elevator. The exit of the tunnel is in the industrial area of San Diego and was enclosed by disposal containers.

Fox News reports that six people were arrested on Friday accused of drug crimes and the tunnel construction. Over the past 10 years under the border of Mexico and the United States such tunnels are found more and more often. The authorities believe that, in addition to drug trafficking, they are also used for delivery of Mexican and Central American illegal migrants to the United States.