Alternative route: A smuggling tunnel kitted out with lights, pumps and ventilation has been discovered running under the Mexican-U.S. border in the city of Nogales
A tunnel running 250 feet beneath the U.S.-Mexican border has been discovered fully kitted out with electricity, water pumps and ventilation.
Authorities in Arizona said although they've found dozens of tunnels in Nogales, a city in Santa Cruz County since the 1990s, this one is by far the most sophisticated.
Chief border patrol agent Randy Hill said those who were building it had chiselled through solid rock and installed lighting and other equipment.
Border patrol found an entrance to the tunnel on May 2 in an abandoned building. An investigation has begun with the U.S. Drug Enforcement Administration and the Mexican government.
The tunnel lies 15 feet beneath the ground and is three feet wide and five feet high.
Chief Hill said: 'This tunnel is more sophisticated than other recently discovered tunnels. They chiselled through solid rock and then installed electricity, lighting, water pumps, and ventilation.'
'It is a prime example of the risks traffickers will take and the lengths they will go to smuggle contraband into our country.'
The state of Arizona straddles a heavily trafficked route for powerful Mexican cartels smuggling marijuana, cocaine, heroin and methamphetamines into the U.S.
Security has been tightened along the shared border in recent years leaving drug smugglers no option but to burrow underground to try to evade detection.
At least eight tunnels have been found running beneath the streets on both sides of the border since October last year.
Last weekend, 12 suspected members of a powerful drug gang and a member of Mexico's Navy were killed in a shoot-out on an island lake that straddles the U.S.-Mexico border.
Drug traffickers used the island on Falcon Lake, located between Texas and the Mexican state of Tamaulipas, for storing marijuana to be transported by boat to the United States.
Sophisticated: The tunnel, which runs across the Arizona state border, is used by Mexican drug cartels to move their stashes into the U.S.
Resourceful: Authorities have found eight similar tunnels in the last six months