Carlos Puigdemont, Catalonia's pro-independence president, has said the autonomous region's independence referendum is a moment for his compatriots to "express our will as a people, remembering the past, where we come from, but also to project ourselves into the future".
Large pro-independence crowds gathered in Barcelona this morning in support of the Catalan regional government after news of the raids broke.
"We condemn and reject the anti-democratic and totalitarian actions of the Spanish state", he said, adding that Catalans should still turn out in force to vote in the referendum on a split from Spain that the central government in Madrid has declared illegal.
The first of hundreds of Catalan mayors summoned to answer questions on why they have backed a banned October 1 referendum on independence from Spain appeared before the state prosecutor on Tuesday amid cheers and chants from supporters.
The searches are a continuation of Tuesday's operation, in which police seized a significant amount of documents (envelopes and instructional pamphlets) related to the referendum at Unipost, Catalonia's biggest private mail-delivery company.
Another leading citizens' agency, the Federation of Barcelona Neighbours, called on people to take to the streets in defence of Catalonia's institutions.
The club also says it "will continue to support the will of the majority of Catalan people, and will do so in a civil, peaceful, and exemplary way".
In November 2014, a non-binding vote on independence for Catalonia showed 80 percent of people were in favor.
Puigdemont described the raids as "a coordinated police assault", which he said showed that Madrid "has de facto suspended self-government and applied a de facto state of emergency" in Catalonia.
The detainments were authorized by Madrid in an effort to deter the October 1 referendum vote to determine if the autonomous province of Catalonia will separate from Spain and become its own sovereign nation.
Summary: The Catalonia area is in an uproar after the Spanish government swooped in, arresting several top officials to prevent an independence referendum from being held. Officials said 80% of them backed independence.
Regional officials have vowed to hold the referendum on Catalonia's secession from Spain despite fierce opposition from the central government and a suspension order by the Constitutional Court.
A crowd of protesters gathers outside the Catalan region's economy ministry after junior economy minister Josep Maria Jove was arrested in Barcelona, Spain, September 20, 2017.
Jordi Sole and Josep-Maria Terricabras from the Green group and Ramon Tremosa from the Liberals called on European Union commissioners "to not remain indifferent" to what they called Spain's "siege" of Catalonia.
Sturgeon said the Edinburgh Agreement, drawn up by the Scottish and United Kingdom governments before the 2014 independence referendum in Scotland, could act as a template for others.