⁍ The tunnel was found on Tuesday in the desert near San Luis, Arizona.

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⁍ Authorities have located hundreds of tunnels under the Southwest border.

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⁍ The tunnel included a ‘ventilation system, water lines, electrical wiring, rail system, [and] extensive reinforcement

– US Immigration and Customs Enforcement officials are calling it “the most sophisticated tunnel in US history” and “certainly the most sophisticated I’ve seen in my career.” The 1,300-foot tunnel, discovered near the Arizona-Mexico border on Tuesday, includes a “ventilation system, water lines, electrical wiring, rail system, [and] extensive reinforcement,” ICE said in a press release Friday, per Reuters. The tunnel, which is still under construction, is believed to be used by drug cartels and criminal organizations to smuggle narcotics, people, and weapons back and forth between the two countries. The tunnel was discovered after federal agents discovered a sinkhole near cross-border fencing in mid-July, ICE said. Carl Landrum, a US Customs and Border Protection official, said the tunnel “appears to be the most sophisticated tunnel in US history, and certainly the most sophisticated I’ve seen in my career.” In January, CBP announced the longest cross-border smuggling tunnel ever found along the Southwest border, originating in Baja California, Mexico. It measured 4,309 feet. President 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.