A tunnel used by traffickers to move drugs from Mexico to the United States was discovered Saturday under the common border.
The 300-meter-long tunnel, with a diameter of 2.0 meters, is equipped with rails and carts to transport marijuana and cocaine, the Mexican Attorney General's office (PGR) said on Saturday.
The structure linked a house in downtown Mexican border city Nogales in the northern state of Sonora with the US territory.
Six people were arrested in relation to the tunnel, including apolice chief, a former police agent and the leader of a drug-trafficking ring, said Jose Luis Santiago Vasconcelos, an officialat PGR's Under-director's Office for the Specialized Investigationof Organized Crime.
The police chief was accused of protecting the activities of the ring, which appears to have ties with the outlawed drug lord, Joaquin Guzman, alias "El Chapo," Vasconcelos said.
The tunnel was discovered as part of the PGR investigation dubbed "Mole II" that included a raid on three houses in Nogales, he added.