Spanish police have arrested 13 people accused of belonging to the Venezuelan criminal group Tren de Aragua, in what authorities said was the first major operation in Spain targeting the gang.

Police said Friday the arrests were carried out in five cities — Barcelona, Madrid, Girona, A Coruña and Valencia — as part of an operation to dismantle a suspected cell of the Venezuelan prison gang, which the U.S. government designated as a foreign terrorist organization earlier this year.

As part of the raids, officers also shut down two laboratories used to produce tusi — a synthetic drug made from a mix of cocaine, MDMA, and ketamine — and seized other narcotics, including cocaine.

The investigation began last year after the arrest in Barcelona of the brother of “Niño Guerrero,” the leader of the Tren de Aragua gang, under an international warrant issued by Venezuelan authorities.

Tren de Aragua originated more than a decade ago inside a notoriously violent prison in Venezuela’s Aragua state. The group has since expanded across Latin America and beyond, taking advantage of the mass exodus of Venezuelans — more than 7.7 million people — fleeing the country’s economic crisis.

Police said the operation marks a significant step in curbing the gang’s growing international reach and influence in Europe.