In a statement, the National Maritime Authority (AMN) said that the joint operation with the Portuguese Navy and the Air Force resulted in the identification of the men being of Spanish nationality, aged between 33 and 55 years, intercepted during the monitoring of "suspicious movements" of the vessels.

According to that authority, "two operations were carried out in international waters, targeting these vessels", about 80 nautical miles, equivalent to about 148 kilometers, south of the continental territory.

"One of the approaches was carried out by the Navy, operated by the Marines, and the other was carried out by the National Maritime Authority, through the Maritime Police," the statement continued.

The vessels were taken to the port of Faro in order to carry out the investigation efforts, as well as the four men.