In a mass act of civil disobedience, organized by WhatsApp groups, encrypted messages and clandestine committees, a small army of parents and their children occupied hundreds of polling stations across Catalonia on Saturday, hoping to thwart efforts by the central government to shut down an independence referendum that Madrid calls illegal.

The remarkable occupation of elementary and high schools, which in Spain serve as polling stations, set the stage for an almost surreal confrontation between pro-independence Catalans and their central government.

The defenders of the vote were not trained cadres of activists, but ordinary, overextended and stressed parents from the neighborhoods, who carried babies on their hips and entreated rambunctious children to stop teasing their siblings.

As the occupiers were gulping coffee and sharing plates of pastries brought by volunteers, police units on Saturday started to sweep the schools to warn the parents that the buildings must be emptied by 6 a.m. Sunday, three hours before the controversial plebiscite is scheduled to begin.

Police have been instructed to clear the polling places but to use limited force.

As children ran around chasing soccer balls on playgrounds and scribbled with crayons in classrooms, their parents were huddled in the hallways, sneaking a quick cigarette, scrolling their cellphones and worrying.

"I would not deny that we are nervous, because we don't know what is going to happen," said Roger Serra, a parent who spent the night at Enric Casassas primary school here alongside about 50 others.

[In Catalonia’s independence vote, students want their say]

The people who came to occupy the buildings to defend the referendum were almost in disbelief that in a prosperous, stable and globalized country in Europe in 2017, they suddenly found themselves at a modern-day version of the old barricades.

The families spent a restive night, watching Disney movies and curled in sleeping bags.

Catalonia's secessionists, led by the region's pro-independence president Carles Puigdemont, vow to press ahead with the vote — in rebellion against the central government in Madrid and the Constitutional Court, which has declared the referendum illegal and the results, whatever they might be, illegitimate.

Spanish Prime Minister Mariano Rajoy has moved thousands of national police and Guardia Civil militia into Catalonia to stop the plebiscite.

National security forces have confiscated more than 13 million ballots, shut down websites, arrested 14 functionaries and demanded that the region's 700 mayors desist from supporting the vote.

On Saturday, national police took over the regional government's telecommunications center in Barcelona. A court in Barcelona ordered Google to delete a mobile app the Catalan government was using to distribute information about how and where to vote.

Officials with the central government told reporters that police had secured about 1,300 of 2,315 schools in Catalonia used as polling stations. The same officials also said that activists had occupied 163 schools. Those figures could not be verified and were challenged by pro-independence activists who said many more schools were filled with supporters of Sunday's vote.

The activists, who asked that their identities remain anonymous because their activities are deemed illegal, said it was also possible that even if normal polling places are closed, the vote could be staged down the block at another public building that someone has the key to.

"Can we vote, or not? For me the great question is, who is going to bring the ballot boxes and ballot papers? Will they come from a hidden place, some clandestine, secret place, that could be in our town and from there they are going to distribute it? I don't see how this will work," said Victor Colomer, who spent the night in the school with his wife.

The regional government says it has printed millions of ballots and has stashed them around Catalonia, playing a cat-and-mouse game with police.

Along with the hidden ballots are thousands of plastic tubs, marked with the Catalan regional government's emblem, with numbered, red strips normally used to secure the ballots after they are dropped in the boxes.

At a news conference, Catalan officials showed off one of the ballot boxes. Puigdemont told reporters that more than 6,000 were being cached.

One Catalan pro-vote activist told The Washington Post that the referendum would proceed "as normal as possible in an abnormal situation" — that citizens would go to their traditional polling station, usually a neighborhood school, show their identification card, be checked against the voter registries maintained by the regional government and cast their ballot — yes or no for independence.

After the vote, the volunteers are to tally the count and report it to the regional government, which will announce the result.

[Catalan farmers drive hundreds of tractors through Barcelona in support of independence vote]

But it is far from certain that this will happen as promised by Catalonia's separatists.

The Spanish foreign minister, Alfonso Dastis, told Sky News that there would be no real vote.

"There are no voting places, no ballot papers, no authorities to check the authenticity of the results," Dastis said. "There may be some type of simulation of a vote in certain places and streets, but I don't believe that there will be any referendum."

Police have threatened not only to shut down the schools but also to issue large fines to anyone assisting an illegal vote.

The mayor of Sabadell, the fifth-largest city in Catalonia, said there were 54 polling stations here. He guessed that half were occupied by parents on Saturday.

"I cannot tell you how the people will vote. Many want independence, many don't. Some are not so sure," said Mayor Maties Serracant, who declined a summons to appear before prosecutors last week.

"The situation is incredible," Serracant said. "If you would have told me a few months ago that parents would be occupying this school to vote, I would have laughed."

The potentially chaotic vote raises immediate questions about its legitimacy. Catalan officials have also sent mixed messages: Is the referendum binding? Or, if the vote tilts toward independence, is it just the beginning of a new round of negotiations with the central government?

Those who want an independent Catalonia often say they've never been a true part of Spain, that they belong to a unique region with its own language, history and culture. They say they have surrendered too much control — and too many euros in taxes — to the central government in Madrid.

Those who want to remain in Spain say the country is indivisible, that it is better to belong to "Big Spain" than "Little Catalonia," a country that would hold just 7 million people.

Many, especially those who want to remain a part of Spain, said they were afraid to vote. Others said they would not enter a building illegally — or did not want to walk through a phalanx of police officers in riot gear.

"I think the vote is illegal. I don't want to vote tomorrow. I will stay at home. It's their game — we don't want to play with them," said Jarei Gual Navarro, an engineering student. "We Catalans have always been a part of Spain."

There were demonstrations by pro-Spain voices in Barcelona on Saturday afternoon.

"This vote is not legal, not legitimate and not fair," said Carlos Abril, a finance manager, who came out to wave a Spanish flag.

Abril called himself a proud son of Catalonia but said he opposes independence, which he said would be a disaster for the region. "No debate, police in the streets, lies, fear, violations, propaganda! Man, this is no way to stage a vote."

Raul Gallego Abellan contributed to this report.

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