The Colombian authorities say they have seized at least six tons of cocaine in a warehouse in the Caribbean port of Cartagena.

Police said the cocaine was hidden in false walls in metal drums that were due to be loaded onto a cargo ship bound for Cuba.

One man has been arrested.

It's the second big drug seizure in Cartagena this year -- in July seven tons of cocaine was discovered, disguised as nylon for shipment to the United States via Mexico.