The Catalonian government on Thursday launched its official campaign for an independence referendum, which Madrid has declared illegal, buoyed by the support of the capital Barcelona.
Crowds filled a bull ring in the northeastern city of Tarragona, applauding and shouting "We will vote!" as regional president Carles Puigdemont arrived to rally support for the October 1 vote.
In a boost for the credibility of the referendum, the mayor of Barcelona said earlier on Thursday that the vote would go ahead in the city, having previously expressed concern that civil servants involved may lose their jobs.
A town hall spokesman was unable to comment further or explain how civil servants could be protected.
Puigdemont himself is facing criminal charges of misuse of public money, disobedience and abuse of office for organizing the referendum, and prosecutors have summoned hundreds of the region's mayors for questioning.
Police raided a newspaper office and a printing press last week, looking for signs of preparation, and the regional court has ordered Civil Guard agents to shut down web pages providing information about the referendum.
Regional home affairs councillor Joaquim Forn said there was a bigger than usual presence of national police in Catalonia.
"They are moving throughout the region. They must be looking for ballot boxes," he told RAC1 radio.
A majority of Catalonia's 5.5 million voters want to have their say on the northeastern region's relationship with Spain, but the independence cause has lost support in recent years and surveys indicate less than 50 percent of the population would choose full self-rule.