The gang, which was "highly skilled in robberies" carried out 71 break-ins, stealing jewellery and high-end watches, 64 of which were in the southern resort of Marbella and the rest in Malaga, Torremolinos and Estepona.

In a statement, police said they arrested six people, including the ringleader, an Albanian national who was a military expert in "boarding (ships) and counter-surveillance who took part in all of the robberies carrying a gun".

The group members were former soldiers who used "equipment to communicate between themselves that was commonly used by ex-military personnel" in eastern Europe.

"With their knowledge of military techniques, they used strict personal security and counter-surveillance measures while moving around on foot or in vehicles, changing direction or making unexpected stops," it said.

"They were also trained to access any type of property, regardless of the height of its walls and perimeters, and to act quickly and efficiently."

Before the break-ins, the gang would "exhaustively" stake out the houses, which were often located by golf courses in areas tricky for the police to monitor but easy for making a quick getaway, the statement said.

On four occasions, they used violence and intimidation against homeowners.

Investigators were able to track them by the vehicles they were using, mostly hire cars which they changed frequently, using false documentation with the help of a Spanish businessman based in Malaga.

They were charged with armed robbery with force, belonging to a criminal organisation and money laundering.