Guatemalan authorities say they have intercepted the largest cocaine shipment in the country's history on a cargo ship in international waters off the Pacific coast, in cooperation with the U.S. Coast Guard.

An army statement says the cocaine was hidden in false-bottomed compartments on the Tanzania-flagged ship. So far authorities have compiled 3 tons of drugs, but the inspection continues and that figure could rise.

Military spokesman Oscar Perez confirmed Tuesday that the drug in question was cocaine. He said U.S. authorities were carrying out the search of the vessel and will be the ones to take custody of the drugs.

Guatemala's navy reported that 13 people were detained, including citizens of Colombia, Ecuador and Peru.