Two of the crew were captured, but one managed to swim away and escape.

Madrid, Spain – A submarine carrying three tonnes of cocaine, worth approximately 100 million euros ($110m), has been intercepted after an international operation off the coast of Spain.

The vessel ran aground in waters off Galicia in northwestern Spain while carrying the “high-quality” illicit cargo on Sunday, police said.

The submarine had been tracked while it sailed across the Atlantic from Colombia to Europe.

The Maritime Analysis and Operation Centre, an inter-governmental body based in Lisbon which combats the transport of drugs at sea, and spotter planes from the US Drugs Enforcement Agency worked with the Portuguese and Spanish police to track the vessel.

Portuguese police alerted their counterparts in Spain on Friday that the submarine was heading into Spanish waters to deliver its cargo.

A Portuguese police source said: “The submarine had travelled about 7,690 kilometres or 4,778 nautical miles. It stopped off in Cape Verde, then headed on to Portugal. It was about 40 miles off the coast of Portugal and then headed north towards Spain.

“Intelligence reports said it was carrying 3 to 3.5 tonnes of high-quality cocaine. That would be worth about 100 million euros on the street.”

Into the deep

The submarine’s crew is thought to have planned to transfer the drugs to a fishing ship in waters off Asturias, in northern Spain, but the operation was cancelled – so it returned to the seas off Galicia.

Police were lying in wait for the submarine when it ran aground.

Two men in wet-suits tried to swim away but were captured. A third managed to escape.

Police said two Ecuadorian men were arrested and a Spaniard is still being sought. The detainees will appear in court later on Monday.

Spain’s Underwater Activities Special Group have sent agents to the scene to investigate [Salvador Sas/EPA-EFE]]

A spokesman for the regional government in Galicia, who also declined to give his name, said: “An international operation was able to locate a small submarine about 22 metres (72 feet) long which was near the beach of Hio in the province of Pontevedra.”

Javier Losada, a representative of the Spanish government delegation in Galicia, said: “The seizure of the submarine has involved a combined operation between the Civil Guard, the National Police force and customs officers.”

Helicopters and flotation equipment have been dispatched to the area where the submarine was seized to raise the vessel from the sea bed – but efforts have been hampered by bad weather.

Resources have also been diverted to try to refloat a chemical tanker which ran aground off Galicia last week.

Submarines are routinely used by drugs gangs in Latin America to evade the attentions of the authorities but are still a novelty in Europe.

A police investigator involved in the capture of the submarine this weekend said the vessel appeared to be an expensive boat, costing in the region of 2.5 million euros ($2.8m).

In 2006, five men were arrested in connection with the capture of a homemade submarine which was found in Vigo, also in Galicia.

Five years later, they were jailed for two years each for attempting to use the submarine in a failed attempt to bring 750kg of cocaine into Galicia.

Spain’s supreme court later increased their sentences by a year on the grounds that using such a vessel was an aggravating factor.

The rivers or inlets of Galicia have long been a smuggler’s paradise, but in recent years drug clans have converted them into one of the main entry points into Europe for Colombian cocaine.