Federal agents discovered a drug smuggling tunnel that leads from Tijuana, Mexico, to a warehouse in Otay Mesa.

The investigation started after officials suspected smuggling of narcotics into the U.S. via a cross-border tunnel. The U.S. exit point was discovered after the execution of the warrant, the San Diego Tunnel Task Force said.

The tunnel is about 2,000 feet long, has an average depth of 31 feet and is three-feet wide through most of the passageway, according to authorities. Authorities estimate the tunnel to have been in existence for several months.

Authorities seized five different types of drugs including, 1,300 pounds of cocaine, 86 pounds of methamphetamine, 17 pounds of heroin, 3,000 pounds of marijuana and more than two pounds of fentanyl, for a total of  $29.6 million in mixed drugs.