March 31 (UPI) -- U.S. border officials seized over 4,000 pounds of illicit drugs from the U.S. exit of a tunnel spanning more than 2,000 feet from a warehouse in Mexico to one in California, U.S. Immigration and Customs Enforcement said Tuesday.
The tunnel originates from a warehouse in in Tijuana, Mexico, and extends under the U.S.-Mexico border to a warehouse in the Otay Mesa area of California.
Federal agents on the San Diego Tunnel Task Force discovered the tunnel on March 19 following an investigation that also included ICE's Homeland Security Investigations, U.S. Border Patrol, the Drug Enforcement Administration and the U.S. Attorney's Office, an ICE statement said.
The San Diego Tunnel Task Force was investigating a transnational criminal organization suspected of smuggling drugs into the United States. The agents worked with the attorney general of Mexico and the Mexican secretary of national defense to locate the tunnel entrance.
They presented evidence to a U.S. federal judge and obtained a federal search warrant, which allowed them to uncover the the tunnel's exit.
The drugs seized included approximately 1,300 pounds of cocaine, 86 pounds of methamphetamine, 17 pounds of heroin, 3,000 pounds of marijuana and more than 2 pounds of fentanyl.
U.S. Attorney Robert Brewer said in a statement they amount to an estimated total street value of $30 million.
"If cartels keep spending millions of dollars building tunnels, we will keep finding and filling them," Brewer said. "This is the most valuable single-day tunnel seizure in recent memory, and it is the largest seizure of multiple drugs in a single tunnel. This take down is even more significant in the face of a global pandemic, where stopping the movement of unauthorized people and packages across international borders is of utmost importance."
The tunnel spans more than 2,000 feet with an average depth of 31 feet, and it's 3 feet wide through most of the passageway, the statement said. Agents estimate it's been around for several months because of its "advanced construction" in the passageway, including "reinforced walls, ventilation, lighting and underground rail system."
Earlier this year, Border Patrol agents and other authorities discovered the longest underground cross-border smuggling tunnel, stretching 4,309 feet from Tijuana airport to Greater San Diego.