About 2,000 students gathered on Friday around and inside one of Barcelona's main universities, carrying pro-independence flags and banners supporting the vote, and shouting slogans in support of the arrested officials.
Members of the Catalan National Assembly, a group of separatist activists, set up a security cordon outside the economy department's headquarters, trapping a Civil Guard squad inside as demonstrators vandalized their vehicles.
The Spanish government is headed for a showdown with regional police in Catalonia amid signs the 17,000-strong force isn't fully committed to upholding a court ban sought by Madrid on a planned referendum on independence.
Students occupied the University of Barcelona on Friday, September 22, in another grand display of support for the referendum on Catalan independence planned for the start of next month.More news: I students react to BYU decision to sell caffeinated sodas
But Catalan officials remain defiant, pledging to forge ahead with the referendum. A statement said the six declined to testify.
Mr Forn said the top police officer in the Mossos d'Esquadra had expressed his opposition to the measure during a meeting Saturday with the top state prosecutor in Catalonia and chiefs of Spain's two national police forces, the National Police and the Civil Guard.
Around 40,000 people protested outside the Catalan economy ministry in Barcelona as police raided the building and arrested the regional economy minister, Josep Maria Jové.
Meanwhile, hundreds more pro-independence supporters protested outside a courthouse in the north-eastern Catalan town of Hospitalet de Llobregat to demand the release of the arrested officials. The Spanish government called the bill illegal and challenged it in the Constitutional Court.More news: Ali Zafar breaks silence on internet trolling of Mahira Khan
Even so, he remained confident there will be a large turnout of Catalans on October 1-whatever form the vote takes.
Catalan Vice-President Oriol Junqueras acknowledged that the crackdown had disrupted the referendum plans, saying, "It's evident that we won't be able to vote as we have done in the past".
The region has about 5.5 million eligible voters, and polls consistently show the region's inhabitants favour a referendum but are roughly evenly divided over independence from Spain.More news: Julia Louis-Dreyfus Makes Emmys History for Veep Win