The U.S. Mexican border uncovers the smuggling tunnel sometimes long enough to publish details and images

According to foreign media, there was an elevator, rail tracks, draining and air ventilation system, and high - tension electric cables, followed by Telegram.

He reportedly linked an industrial area in the Mexican town of Tijuana with the San Diego area in California.

But according to foreign media, so far there are no detainees and no drugs have been found. Also, authorities have not said who the tunnel builder is suspected of.

But Mexico's Sinaloa cartel, described by the American government as one of the largest drug trafficking organisations in the world, operates in the area.

Its founder and longtime leader, Joachim “El Chapo” Guzman, he's serving a U.S. life sentence.

It is further known that the tunnel has an average depth of 13 feet [21 m] below the surface, with the tunnel about four feet [1.7 m] high and about 20 inches [60 cm] wide.

However, it was not clear how long it took to build it.

“The selection and length of this particular tunnel shows long efforts by transnational criminal organisations to facilitate cross-border smuggling”, Cardelle Morant, a special agent at the head of the National Security Investigations in San Diego, said in a statement.

As it further becomes known, several hundred sandbags were discovered blocking a suspected former tunnel exit in the San Diego industrial depot area, and the main tunnel had an incomplete flow.

In contrast, more than a dozen sophisticated tunnels have been found at the California border with Mexico since 2016. The second - longest U.S. tunnel, found in San Diego in 2014, was about 900m long.

US President Donald Trump has made construction of a border wall one of his main priorities, saying it is necessary to address illegal immigration and drug trafficking.

But officials say most drugs are smuggled through legal entry, hidden in private-owned vehicles or transport trucks, mixed with other goods.