Barcelona (AFP) - Spanish police on Wednesday seized millions of ballot papers in Catalonia due to be used for an independence referendum which has been banned by Madrid, a source close to the case said.
The source, who requested anonymity, told AFP that officers were currently counting them again, but that the number of ballots confiscated in Bigues, about 45 kilometres (28 miles) north of Barcelona, could reach nine million.
The seizure comes as thousands took to the streets in Barcelona on Wednesday over the detention of 13 Catalan government officials as the wealthy northeastern region presses ahead with preparations for the October 1 vote.
Catalonia's separatist leaders want the region's 7.5 million inhabitants -- who are deeply divided over the issue -- to be able to answer the question: "Do you want Catalonia to be an independent state in the form of a republic?"
But the country's Constitutional Court has deemed such a referendum illegal.
The constitution states that the unity of the Spanish nation is "unbreakable" and that only the central government has the power to call a referendum on any matter.
Catalan separatists have retorted that they have a democratic right to decide on their future.
Operations were also underway Wednesday at several offices of the Catalan executive, including the presidency and the departments of economic and foreign affairs.
Over the past few days, police have ramped up their seizures of items that could be used in the referendum, including notifications which were about to be sent to Catalans selected to staff polling stations.
Madrid has also threatened to arrest mayors who facilitate the vote and has tightened its control over the region's finances.
Separatist parties captured 47.6 percent of the vote in a September 2015 Catalan election which was billed as a proxy vote on independence, giving them a narrow majority of 72 seats in the 135-seat Catalan parliament.
But opinion polls show that Catalonia remains divided on seceeding from Spain.
A survey commissioned by the regional government in July showed that 49.4 percent of Catalans were against independence while 41.1 percent were in favour.