At least 460 Catalans were injured on Sunday as the Spanish Police used force in their attempt to block voting in a referendum seeking independence for Catalonia. A spokesperson for the Catalan government had earlier said that the injured had been asked to file complaints with the state police.

The Spanish Police were in riot gear as they tried to stop people from voting. There were constant attacks on the computer systems as well, said Jordi Turull of the Catalan government.

The mayor of the regional capital Barcelona, Ada Colau, called for an “immediate end” to police action against the “defenceless population”. They prevented several potential voters from entering voting booths and also seized ballot papers and boxes, the BBC reported.

Eleven police officers were also injured, the Spanish Interior Ministry said.

Voting had begun at 9 am. About 73% of the polling stations across the Catalan region in north-eastern Spain opened for voting on Sunday, despite efforts by the police to block the referendum, the Catalan government said.

The police fired rubber projectiles at people lining up to vote in Barcelona, AP reported.

Tensions between Madrid and Catalonia have been high since a Spanish court declared the referendum unconstitutional on September 7. The Spanish government had also pledged to not allow the vote happen.