MEXICO CITY (Reuters). – U.S. drug enforcement agents discovered a tunnel for drug smugglers that runs under the U.S. – Mexico border. The tunnel was equipped with a railway track, electricity, ventilation, according to the U.S. Department of Justice.

According to the Department of Public Safety, this so-called “narco tunnel” ran from Tijuana, Mexico, to San Diego, California. It was located 300 feet away from San Diego’s border.

Six people were arrested by U.S. officials for their involvement in the drug-running plot. Six people were arrested by U.S. authorities for allegedly conspiring to distribute heroin, cocaine and methamphetamines, along with other criminal acts.

U.S. Attorney Randy Grossman said in the statement that there was no longer light at end of the narcotunnel.

It is estimated that the tunnel measures more than 1,750ft (530m). The walls were reinforced.

According to the Mexican attorney general, Tijuana was located in Baja California. The U.S. authorities were notified of its discovery by Tijuana’s office on Sunday.

Mexican authorities claim that many tunnels were created by the Sinaloa cartel in Mexico, which has been led over years by Joaquin “El Chapo” Guzman.

According to U.S. Prosecutors, nearly 100 tunnels have been discovered in the area since 1993.

According to the Baja California attorney General’s Office, it was the longest tunnel in the area.

Mexico’s Federal prosecutor’s Office didn’t respond to our request for comment.