WASHINGTON (CNN) -- Authorities have found what they call the largest tunnel running into the United States along the U.S.-Mexican border.
About 2 tons of marijuana were inside the tunnel, the Drug Enforcement Administration said, indicating that it appears to have been used to transport drugs.
DEA and U.S. Immigration and Customs Enforcement agents discovered the tunnel Wednesday night. It runs from Tijuana, Mexico, to Otay Mesa, California.
Officials said the tunnel is about seven-tenths of a mile (1,148 meters) or more than 1,200 yards long. Initial reports said it is 5 feet high and 3.5 feet wide.
Made of concrete, the passageway had lighting, electricity, ventilation and a pump to remove water, said Lauren Mack, a spokeswoman for Immigration and Customs Enforcement.
Most of the marijuana was uncovered on the Mexican side, but some of it was in the United States, Mack said.
"It's definitely expected to be related to a major drug cartel in Mexico," she said. No arrests have been made.
An investigation is under way to determine who helped build the passageway.
Mack said human intelligence led to the discovery of the underground structure. Agents then used ground-penetrating radar technology from the military to find anomalies in the soil, she said.
Earlier this month, U.S. border patrol agents investigating a caved-in road discovered another tunnel between Mexico and the United States, west of the San Ysidro, California, port of entry.
It was the third such tunnel found in three years near the San Ysidro port, Mack said. Others were discovered in 2003 and 2004, she said.
"We found trash and other evidence indicating people had been inside recently," Mack said in a phone interview January 11, describing the passage as "primitive."
Tightened border security since the September 11, 2001, attacks is the likely cause for the increase in the tunneling, Mack said.
At least 15 tunnels have been uncovered in California and Arizona since 9/11, she added.
"We've now got a dedicated tunnel task force, which works with the DEA and border patrol to proactively look for tunnels," Mack said.
http://www.cnn.com/2006/US/01/26/mexico ... index.html