Catalan separatists and supporters of the region's right to hold a referendum on independence from Spain have held a rally backing more than 700 mayors facing the threat of arrest.
The mayors have been called in for questioning by prosecutors for agreeing to facilitate the vote locally.
They could be arrested if they do not attend and prosecuted for using public funds if they help stage the ballot.
Madrid has promised to block the vote, saying it is unconstitutional.
Catalonia's regional government insists it will take place as scheduled despite a growing clampdown by the Spanish state.
Some of the mayors gathered with Catalan President Carles Puigdemont outside the headquarters of the regional government, the Generalitat Palace, as supporters waved the lone-star flag of the independence movement.
"We stand firm against threats, censorship and prosecution and repeat this: we want to be a free country," Mr Puigdemont told the crowd, according to a tweet by the Catalan National Assembly grassroots independence movement.
Chants of "We will vote" could be heard from the crowd.
Barcelona Mayor Ada Colau, who supports the right to hold the referendum, also turned up.
"It's a disgrace that we have a government that is incapable of dialogue and instead dedicates itself to pursuing and intimidating mayors and the media," she said.
Ms Colau announced on Thursday that people in Barcelona would be able to vote without civil servants involved risking their jobs but did not explain how.
'It won't happen'
On Friday, the Spanish government gave the regional government 48 hours to abandon its "illegal" referendum plans or lose budgetary powers.
"If, 48 hours from now, there's no compromise that falls within the law, from then on the Spanish government will take over responsibility for making Catalonia's payments," Spanish Prime Minister Mariano Rajoy later told a meeting of his Popular Party in Barcelona.
"My friends, I say this both calmly and firmly: there will be no referendum, it won't happen."
Mr Rajoy also announced that police from Spain's national Guardia Civil force had seized 100,000 referendum posters.
No government in the world, he said, could accept one of its regions unilaterally scrapping the nation's constitution and its laws.
Attempts to block the official referendum website have continued.
Thousands of ballot boxes are said to have been hidden by referendum supporters. Police have been hunting for them but Toni Castejon, spokesman for the Catalan police force, admitted "right now, we have no idea where they are", the Reuters news agency reported.