Shocking: US officials uncover 'sophisticated' smuggling tunnel on Mexican border

San Luis: U.S. authorities have discovered an unfinished 1,300-foot (400-meter) tunnel under the U.S.-Mexico border, calling it an unusually sophisticated smuggling route complete with ventilation and a rail system.

The tunnel was found on Tuesday (August 4) in the desert near San Luis, Arizona by federal agents led by U.S. Immigration and Customs Enforcement's investigative (ICE) arm, the agency said on Friday. Authorities have located hundreds of tunnels over the years under the Southwest border, saying they are used by drug cartels and criminal organizations to smuggle narcotics, people and weapons back and forth between the two countries.

The tunnel found this week measured 3 feet by 4 feet (91 cm by 1.22 meters) and included a ventilation system, water lines, electrical wiring, rail system, extensive reinforcement authorities said. Federal agents drilled and used underground cameras to investigate the tunnel after discovering a sinkhole near cross-border fencing in mid-July, ICE said.

Vinny Dulesky, a Public Affairs agent for Yuma Sector U.S. Border Patrol, said the tunnel appeared to be one of the most sophisticated tunnels ever seen in U.S. history. In January this year, CBP announced federal agents had discovered the longest cross-border smuggling tunnel ever found along the Southwest border, originating in Baja California, Mexico. It measured 4,309 feet (1,300 meters).

President Donald Trump has pledged to build a wall on the border with Mexico to stop illegal crossings and drug trafficking, but critics point to tunnels as one way people can get around such a barrier.