The tunnel was found on Tuesday in the desert near San Luis,
Arizona by federal agents led by U.S.
immigration and Customs Enforcement's investigative arm, the agency said in a press release 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, [and] extensive reinforcement," ICE said.