One suspect dead following high seas drug interdiction off Portugal

"We are dealing with yet another international criminal structure whose main objective is to bring large quantities of cocaine into Europe using this modus operandi, which has been widely used in recent times," Oliveira said, referring to the speedboats known as narcolanchas.

The six-month investigation, named Operation Mare Nostrum, was coordinated by the Judicial Police's National Unit for Combating Drug Trafficking. It also involved the Portuguese Navy, the Maritime Police, the Portuguese Air Force, Italy's Guardia di Finanza (GdF) financial police, and Spain's Guardia Civil police, under the framework of the Maritime Analysis and Operations Centre – Narcotics.

In July, the GdF intercepted a small boat carrying more than 2.6 tonnes of cocaine in the Atlantic Ocean off Portugal in a separate operation.