(Aljazeera) -- Spain's central government in Madrid, which opposes the referendum, has sent thousands of police reinforcements to the Catalonian capital of Barcelona to stop people from voting.

A court on Wednesday ordered police to prevent the use of public buildings "for the preparation and organisation" of the referendum.

But as classes ended for the day, small groups of activists, including parents with their children, on Friday peacefully occupied several schools in Barcelona where voting is scheduled to take place.

"We want to make sure the school is open for activities and at night when they might come to clear us out or empty it, there will be families sleeping or people in the street," Hector, a 43-year-old local, told Reuters news agency.

"I am going to sleep here, with my oldest son who is a student here," Gisela Losa, a mother of three, told AFP news agency at Reina Vionant primary school in Barcelona's Gracia neighbourhood.

The head of the Catalan regional police has ordered officers to evacuate and close polling stations by 6 am on Sunday, before the voting is due to open at 9 am.

Madrid has repeatedly warned those who help stage a referendum which the courts have ruled unconstitutional that they face repercussions.

Spain's education ministry said in a statement on Friday that school directors in Catalonia "were not exempt from liability" if they cooperated.

The Catalan government says 2,315 polling stations are ready for the October 1 vote.  

Al Jazeera's John Hendren, reporting from Barcelona, said both sides have been preparing for confrontation over the looming vote.

"Clearly, many of the polling stations will be shut down [by Spanish authorities]," he said. "The government of Catalonia has said ... it will declare itself an independent republic if they get the votes."

Final rally 

On Friday evening, about 10,000 supporters of the referendum gathered off Barcelona's Placa d'Espanya, or Spain Square. 

Catalan leader Carles Puigdemont said regardless of how many people actually cast the ballots, if a majority say "yes", he will declare independence on Tuesday. 

"In these hugely intense and hugely emotional moments, we sense that what we once thought was only a dream is within reach," Puigdemont told a cheering crowd.

"On Sunday, we have a date with the future."

Catalonia's foreign affairs chief Raul Romeva told Al Jazeera on Friday the referendum "is impossible to stop" despite the central government in Madrid insisting that the vote is illegal and it will not happen.

Opinion polls show Catalonia's roughly 7.5 million residents are divided on independence.

A survey commissioned by the regional government in July showed 49.4 percent of Catalans were against independence while 41.1 percent were in favour.

More than 70 percent of Catalans want a legal referendum on independence to settle the issue.

(Photo: About 10,000 supporters of the referendum gathered in Barcelona for the final rally Reuters)