Spanish police seized four tonnes of cocaine aboard a ship off the northwest coast of Spain.
Eleven people were arrested in the operation, carried out on Saturday in conjunction with drug enforcement authorities from the United States and Britain, a ministry statement said.
Six of the detainees were arrested aboard the ship, three in Madrid and two more in the northwest region of Galicia.
Police also seized US$27,000 (EUR20,000) and several cars and cell phones.
The discovery of the submarine has unveiled a few "inconsistencies." For example, how can one explain the fact that the sub was found where it needed to be searched for from the start?