Four people have been detained after Portuguese authorities intercepted a narco-sub carrying more than 1.7 tonnes of cocaine in the mid-Atlantic. The semi-submersible vessel was bound for the Iberian peninsula and was seized in recent days, according to officials.

Footage shows the police and navy surrounding the vessel before boarding, seizing the Class A substance and arresting four crew members, who are said to be from South America. The suspects, including two Ecuadorians, a Venezuelan, and a Colombian, were remanded in pre-trial custody after their court appearance in the Azores on Tuesday, said police.

Vítor Ananias, head of Portugal's police unit to combat drug trafficking, told a press conference that their different nationalities showed the organisation behind them was not just based in one country. The Lisbon-based Maritime Analysis and Operations Centre (MAOC) indicated that a criminal organisation was in the process of dispatching a submersible loaded with cocaine destined for Europe.

A Portuguese ship successfully located the submersible approximately 1,000 nautical miles (1,852 km) off the coast of Lisbon, in an operation backed by the UK's National Crime Agency and the US Drug Enforcement Administration. After being seized, the navy could not tow the vessel back due to poor weather and its fragile construction, and it ultimately sank in the open sea.

Ananias highlighted the hardships faced by those aboard the vessel, drawing attention to the extreme conditions that exacerbate the dangers of long-duration voyages at sea. This incident follows a similar case in March, where authorities captured another narco-sub containing 6.5 tonnes of cocaine.

The increasing intensity of drug trafficking operations coincides with heightened enforcement measures by the US, particularly against vessels suspected of smuggling drugs into its territories, which have sparked controversy and raised questions about international law.