Fourteen people suspected of recruiting fighters for the insurgency in Iraq were arrested overnight across Spain.
The suspects were detained in the cities of Lerida, Malaga, Nerja, Seville and on the Balearic islands.
About 100 police were searching the premises at which the suspects were detained.
Spanish media reports said several suspects were of Moroccan origin, others were from Algeria, Egypt and Ghana.
Seven people suspected of financing an Algerian extremist group were arrested on the southern Spanish coast on 9 December.
Four of them were released without any charges the following week while three others were remanded in custody for suspected cooperation with a terrorist organisation.
Last month police arrested 11 people linked to the same group in raids in southern Spain.
