One person was arrested.
No contraband was found in connection with the tunnels, which linked warehouses in Tijuana, Mexico, with warehouses in an industrial park in the Otay Mesa area of San Diego, according to a statement from US Immigration and Customs Enforcement's Homeland Security Investigations.
The first tunnel, stretching about 550 meters, was discovered Tuesday. It was described as being equipped with lighting, a crude rail system and wooden trusses.
The entrance on the US side is inside a warehouse where a cement cap covered a 70-foot shaft. A pulley system was installed to hoist goods into the building, which was filled with children's toys and boxes of televisions.
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The tunnels were the sixth and seventh found in the area in less than four years, ICE said.
"Here we are again, foiling cartel plans to sneak millions of dollars of illegal drugs through secret passageways that cost millions of dollars to build," US Attorney Laura Duffy said in a statement. "Going underground is not a good business plan."