On Friday, the joint Scottish-Spanish operation targeted properties in Bellshill, Glasgow, Gartcosh, Whitburn, Caldercruix, Cumbernauld, Coatbridge, Barcelona and in the Malaga area.
Officers made eight arrests in Scotland and five in Spain.
Det Ch Insp George Calder told BBC Scotland News the investigation was probing alleged high-level involvement in organised crime, drugs and money laundering.
He added: “This day of action has been the result of over two years of investigative work that’s been carried out diligently carried out by officers not only here, but by other agencies, including the National Crime Agency and the Guardia Civil.
“We have got a number of officers over in Spain, assisting the Spanish authorities with their inquiries.
“We’re sharing intelligence, information and resources.”