Spain's central government has sent about 10,000 extra police officers to Catalonia for the referendum.

Catalan police warned on Wednesday that public disorder may erupt as Spain orders the authorities to prevent public buildings from being used as polling stations and stop the region holding a referendum on independence.
The Catalan government has vowed to press ahead with Sunday's plebiscite in the wealthy northeastern region despite a crackdown by Madrid which wants to prevent a vote deemed unconstitutional by the courts.
The showdown is one of Spain's biggest political crises since the end of the dictatorship of General Francisco Franco four decades ago and the referendum has deeply divided Catalonia, which is home to about 7.5 million people and accounts for about a fifth of the country's economy
The Superior Court of Catalonia on Wednesday ordered police to prevent the use of public buildings or places "for the preparation and organisation" of the vote.
The order applies to Spain's national police and the Guardia civil police force, as well as Catalonia's regional police force, the Mossos d'Esquadra.
The order comes a day after Catalonia's chief prosecutor ordered the Mossos to seal off buildings that will house polling stations before Sunday's referendum which Madrid has declared illegal.
The prosecutor also ordered police to deploy officers on the day of the ballot to prevent people from voting.
Pressure increases
But such a step "could lead to undesirable consequences," the Mossos d'Esquadra warned in a posting on Twitter on Wednesday.
"These consequences refer to public security and to the more than foreseeable risk of a disruption of public order that this may generate."
El compliment d'instruccions no exclou la responsabilitat professional de contemplar q aplicar-les pot comportar conseqüències no desitjades
— Mossos (@mossos) September 27, 2017
The Catalan government has said it will set up nearly 2,700 polling stations, the same amount as in the last regional elections in 2015.
The order puts intense pressure on the Mossos' roughly 16,800 officers who are caught between their loyalty to local Catalan leaders who are pushing ahead with the referendum and their pledge to uphold the law.
Anticipating their reluctance, Spain's central government has sent about 10,000 extra police officers to Catalonia for the referendum, according to top-selling daily newspaper El Pais.
"They are likely to prevent people from voting in big cities" which will greatly reduce the number of voters meaning the ballot will have as little legitimacy as possible, a senior judicial source said.
End of stability?
Prime Minister Mariano Rajoy's conservative government is facing mounting criticism over its handling of the crisis.
In a harshly-worded editorial, El Pais daily denounced "the absence of government" and an attitude it said was "disconcerting, inadequate and close to irresponsibility".
"It is up to the government and not to the prosecutor to explain, day after day, what it is doing, what measures it is taking and is about to take."
Deputy Prime Minister Soraya Saenz de Santamaria accused Catalan separatists of seeking to end "the years of democratic stability for which our parents fought."
"We are perhaps living in an unprecedented historical moment because of the determination of certain separatists to deny centuries of shared history between Spaniards," she told parliament.
Polls show Catalans are split on the issue of independence, but a large majority want to vote in a legitimate referendum to settle the matter.