After a day of violence in the region on Sunday when the central government sent in police to disrupt voting in an illegal referendum on independence, Justice Minister Rafael Catala said it would use all the tools at its disposal -- including if necessary the suspension of Catalonia's autonomy -- to enforce the rule of law. The EU for its part said the Catalan matter must be dealt with under the Spanish constitution.

"We have always said that we would use all the force of the law and all the mechanisms that the constitution and laws grant," Catala told broadcaster TVE in an interview. While images of police violence provoked alarmed reactions from some European government officials, Catala praised the security forces for their "measured" response.