Rotterdam police have been involved in a cross-border campaign to break up what Europol describes as a “highly violent criminal cell from the Western Balkans” which was involved in the “large-scale trafficking of drugs and firearms across Europe”.

In total, 37 people were arrested in a string of raids carried out simultaneously across Croatia, Slovenia, Bosnia & Herzegovina, the Netherlands, Italy, Belgium and Germany earlier this week.

The gang is said to have been led by a national from Bosnia & Herzegovina who is currently in jail in Italy. He continued to orchestrate the gang’s criminal activities from his prison cell, Europol said.

The raids turned up €148,000 in cash, 500 grams of TNT with remote detonators and over 15 kilos of cocaine, much of which was found in a garage in the Netherlands.

Croatian police, who led the operation, said the Netherlands was being used by the gang to funnel drugs. There were no arrests in the Netherlands, Europol told Dutch News.