Truck driver pleads not guilty in drug tunnel case

A truck driver accused of carrying almost two tons of marijuana after it was smuggled into the United States through a tunnel running under the U.S.-Mexico border has pleaded not guilty in San Diego.

Federal authorities say they followed Carlos Enrique Cunningham after his tractor-trailer left a San Diego warehouse under surveillance. He was arrested Tuesday and pleaded not guilty Friday to a charge of conspiracy to distribute marijuana.

After securing a search warrant, officials say they found between 10 and 15 tons of marijuana in the warehouse and the entrance to the tunnel, which ran 600 yards underground and ended at a warehouse on the Mexican side.

Officials say the seizure totaling more than 20 tons was one of the largest pot busts in the U.S.