Spain's Civil Guard confiscated a ton of cocaine from South America in several shipments and arrested 18 people in a months-long operation, authorities said Thursday.

The operation enabled law enforcement authorities to dismantle one of the most important drug trafficking networks between South America and Spain, an outfit that had established a significant infrastructure in the Spanish ports of Barcelona and Valencia, the Civil Guard said.

Officers in Barcelona in May seized two containers, one containing 403 kilos of cocaine coming from Nicaragua and the other containing 318 kilos sent from the Dominican Republic.

A month earlier, in Valencia, authorities had seized 225 kilos of cocaine in a container coming from South America and in January they found 10 kilos of the drug at a country house.

Ten of the arrests were made in Barcelona, six in the northwestern Spanish region of Galicia and two in Portugal, according to sources involved with the investigation. EFE