Spanish cops have seized the largest haul of crystal meth in history while busting an international gang that smuggled drugs into Barcelona in hollowed-out concrete blocks.

The Spanish Civil Guard said in a statement obtained by Newsflash that the raid took place in Barcelona, as well as in other cities in Spain, in the Netherlands and in Turkey, resulting in the arrest of 16 people.

The cops said that the criminal organisation was based in Spain and in the Netherlands and was linked to the Mexican Beltran Leyva cartel.

The police said that the criminal organisation was specialised in smuggling cocaine and methamphetamine into Europe through the Port of Barcelona, the capital of the Catalonia region in north-eastern Spain.

The cops said that the investigation had lasted three years and that they had worked in coordination with EUROPOL.

The operation resulted in what the police said was the largest haul of crystal meth in history, with 2,549 kilogrammes (5,620 lbs) of methamphetamine and 1,370 kilogrammes (3,020 lbs) of cocaine being seized.

The Civil Guard added in its statement: “With this police intervention, the main route of introduction into Europe of these narcotic substances through the Port of Barcelona is considered dismantled.

“Those responsible controlled a new way to introduce the drug, which consisted of creating hidden spaces in concrete blocks, making it undetectable before port controls.”

The cops said they began investigating in 2017 after receiving information thanks to international police cooperation regarding an export company that was suspected of being used by Mexican cartels to smuggle large quantities of drugs into European countries through Spain.

The company, which has not been named but which the police said was located in Mexico, is believed to be working with the cartel, which used “precast, concrete, thermal blocks intended for construction”.

The police said that the criminals “took advantage of the infrastructure of their international trade operations, coming from South and Central America, to take over the European market for narcotic substances”.

The authorities have suggested that the aim of the cartel was to “flood” the European market with methamphetamine using “historical cocaine routes that they dominated”.

Another aspect of the operation was money-laundering in Spain. The cops said that they endeavoured to “determine the money laundering structure that the criminal organisation had in Spain, having proven the existence of numerous bank movements with origin or destination in Mexico for high amounts, which were received by the members of the Beltran Leyva cartel.

“This remittance of funds was carried out via the collaboration of Spanish businessmen living in Talavera de la Reina and Valencia, who had designed a complex business network to launder the funds obtained through drug trafficking.”

It is unclear if any of the 16 suspects, who have not been named, had been charged at the time of writing.