Spanish prosecutors called for rebellion and terrorism charges to be leveled against nine activists linked to pro-Catalan independence groups who were arrested Monday on suspicion they may have been preparing to commit violent acts, possibly with explosives. A Civil Guard police statement said the operation in Barcelona was part of an investigation into the radical separatist group, the Committees for the Defense of the Republic (CDR), a grassroots organization that favors northeastern Catalonia's independence from Spain. The group was created during Catalonia's failed bid for independence in 2017 and its members are known for blocking off main roads and clashing with police.

Spain's two main center-right parties welcomed the police operation while two Catalan pro-independence parties demanded that caretaker Interior Minister Fernando Grande Marlaska appear in parliament to explain the operation.

The arrests come just a week before the second anniversary of the banned Catalan independence referendum which triggered one of Spain's biggest political crises. The search operation comes ahead of a verdict next month in the trial of 12 separatist leaders for their roles in the attempted secession in 2017. Alleged violence in 2017 was a key focus of the trial, in which the separatist leaders defended the peaceful nature of their movement.