Police in Spain's northeastern region of Catalonia say they have arrested eight suspected members of a jihadi group with ties to the cells that carried out the 2016 suicide bomb attacks in Brussels' airport and subway.

A police statement says the operation took place Tuesday with raids in five towns, including the regional capital Barcelona.

Police say the arrests followed an eight-month investigation in coordination with Belgian police that linked several of the arrested to jihadist organizations as well as organized crime activity.

Police said the suspects were Moroccans residents in Catalonia and aged between 21 and 39.

Spanish police have arrested some 200 suspected jihadi activists since Spain raised its national security alert to one step below the maximum in 2015.