The haul, from Ecuador, was unloaded at the Lisbon port, police said, adding its officers carried out several searches as part of “Operation Squid” and seized eight firearms, high-end vehicles, as well as various documents and objects.

The drugs, which were found in a warehouse in the western region of Portugal, were hidden inside frozen fish, which was wrapped in plastic and packed in cardboard boxes.

“The way in which the drug was hidden in the frozen fish made it extremely difficult to detect it, and in order to remove it, the fish had to be completely destroyed,” Portugal's Judiciary Police said in a statement.

Those detained, aged between 26 and 59, are suspected of being part of an organized criminal group that imported large quantities of cocaine from Latin America and distributed it across several European nations. The police did not disclose the nationalities of the detainees.

They will appear before a judge as the investigation continues.

The United Nations Office on Drugs and Crime said in its annual World Drug Report last year that cocaine demand and supply were increasing across the world.