‘Longest-ever’ tunnel for smugglers found on Us-mexico border

US authorities have announced the discovery of the longest smuggling tunnel ever found on the south-west border, stretching more than three-quarters of a mile from an industrial site in Tijuana, Mexico, to the San Diego area.

The tunnel featured an extensive rail cart system, forced air ventilation, high voltage electrical cables and panels, an elevator at the tunnel entrance and a drainage system.

While there were no arrests, no drugs found at the site and no confirmed exit point in the US, the length – more than 14 football fields – stunned authorities.

“This one blows past [the second-longest],” said Lance Lenoir, a Border Patrol operations supervisor. “We never really thought they had the moxie to go that far. They continue to surprise me.”

The tunnel exposes the limitations of US president Donald

Trump’s border wall, which stretches several feet underground in the area and is considered effective against small, crudely built tunnels often called “gopher holes”. The one newly announced was found about 21m underground, well below the wall.

The discovery comes as a new section of Mr Trump’s signature wall along the Us-mexico border was blown over in high winds.

Steel panels from the fence in the town of Calexico, California were knocked down on Wednesday.

Following the tunnel’s discovery in August, Mexican law enforcement identified the entrance and US investigators mapped the tunnel that extends a total of 1,313m. The next longest tunnel in the US was discovered in San Diego in 2014. It was 904m long.

The newly discovered tunnel is about 1.68m tall and 0.61m wide and runs at an average depth of 21.3m below the surface, officials said.

Agents discovered several hundred sandbags blocking a suspected former exit of the tunnel in San Diego’s Otay Mesa industrial warehouse area. It went under several warehouses in Otay Mesa, where sophisticated tunnels have typically ended, and extended into open fields.

US authorities say they are confident the tunnel exited in San Diego at one time based on its trajectory.

Lenoir, a veteran on the multi-agency task force of tunnel investigators known as “tunnel rats”, said he made his way through about 15m of sugar sacks blocking the tunnel but couldn’t go any farther.

An incomplete offshoot of the tunnel that extended 1,090m suggested to authorities that smugglers had plugged an initial exit point and were building another.

The suspected previous exit “became unsustainable for whatever reason, so they built a spur”, Border Patrol spokesman Jeff Stephenson said.