Mexican authorities shut off access to a sophisticated smuggling tunnel between Tijuana and a San Diego industrial park on Thursday (October 31) after U.S. authorities discovered the "super tunnel" and arrested three suspected to be connected to the operation, officials reported.

Authorities believe the Sinaloa Cartel built and operated the tunnel which travelled 536 metres from Mexico to a rented warehouse in a San Diego industrial area known as Otay Mesa, where most businesses are involved in legal cross-border trade.

The tunnel is fitted with its own electronic rail system, hydraulically operated doors, ventilation and electricity.

U.S. Federal agents confiscated more than 17,000 pounds (7700 kilos) of marijuana and 325 pounds (147 kilos) of cocaine from throughout the tunnel, the first time cocaine has been found in the cross-border tunnels, officials reported.

Since 2008, more than 75 cross-border tunnels have been discovered on the Southwest border between the United States and Mexico, U.S. federal officials reported. Eight completed tunnels have been found in Otay Mesa since 2006.

Presented by Adam Justice