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) said it had received information indicating that a criminal organisation was in the process of dispatching a submersible loaded with cocaine destined for Europe.


A few days later, a Portuguese ship successfully located the submersible approximately 1,000 nautical miles off the coast of Lisbon, in an operation backed by the UK's National Crime Agency and the US Drug Enforcement Administration.


Having seized the vessel, the navy said it could not be towed back to shore due to poor weather and its fragile construction, and it later sank in the open sea.


Vítor Ananias explained that the harrowing conditions faced by those on board the sub highlighted the dangers of drug trafficking. He shared that even a single day under such conditions was a challenge; by the end of several days, the mental strain was substantial.


This instance reflects a pattern of increasing drug smuggling via submersible vessels, with a notable incident occurring in March where a similar craft was found carrying 6.5 tonnes of cocaine.


These events have coincided with intensified measures by the Trump administration against vessels suspected of drug smuggling into the US. The legality of such actions remains a topic for debate among international law experts.