A Civil Guard police statement said the operation in Barcelona province was part of an investigation into the self-proclaimed Committees for the Defense of the Republic, a grassroots organization that favors northeastern Catalonia's independence from Spain. In the past, the group has organized street protests and blocked road and rail lines. It is known by its initials, CDR.
Police said they carried out 10 raids and seized an abundance of material and substances they believe could be used to make explosives. If confirmed, it would be a considerable blow to Catalonia's mainstream independence movement, which is proud of its overwhelmingly peaceful approach since it began gathering momentum in 2011.
National Court prosecutors said the raids were aimed at gathering evidence to demonstrate the CDR's "advanced preparation for terrorist acts in connection with their secessionist aims." The police statement gave few details, saying there was a judicial secrecy blanket order on the case.
And police did not say when the group may have been planning the acts of violence. Major protests in Catalonia are expected in the coming weeks when Spain's Supreme Court issues its verdict in the trial of 12 ex-Catalan officials and activists charged for attempting to establish an independent Catalan republic in 2017.
The prosecutors said the operation was aimed at aborting expected CDR activities around the anniversary of the Oct. 1, 2017, illegal independence referendum in Catalonia and publication of the trial verdict. They said the CDR's activities could have caused "irreparable damage given the advanced state of their preparations."
The CDR issued a statement saying the arrests and raids were a bid to "silence" them and called for protests against what they described as Spanish state repression. In response, more than 100 people gathered in the Catalan town of Sabadell and shouted insults at police carrying out one of the raids.
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.
Catalonia's pro-independence regional president, Quim Torra, criticized the arrests. "Repression continues to be the sole response of the Spanish state," Torra tweeted. "They are trying to construct a tale of violence prior to the sentences. They won't achieve it. The independence movement is, and always will be, pacific."