Riot police are clashing with Catalan voters trying to cast their ballots in a referendum on independence taking place in defiance of the Spanish government Sunday.
The police are using force to try and shut down some polling stations in the north-east region and seize ballot papers.
The police were pictured shooting rubber bullets straight to people trying to reach a voting site at a school assigned to be a polling station by the Catalan government in Barcelona.
Social media has filled with images of officers in tense standoffs with crowds gathered at public schools and sport halls being used as polling sites.
Catalans began occupying the buildings last week in attempt to keep them open for voting.
In some instances, officers wearing helmets and carrying batons were seen dragging people away.
The Spanish government's representative in the region said police intervention was necessary to stop Catalonia's banned referendum.
"We were forced to do what we did not wish to do," Spanish government delegate to Catalonia, Enric Millo, said.
Catalan regional president Carles Puigdemont cast his vote in Cornella del Terri. He could not vote in his regular voting station in Sant Julia De Ramis, outside of Gerona, after it was raided by police officers who smashed glass doors to enter.
"President Puigdemont votes. They cannot silence the voice of the people. We will vote and we will win," pro-independence campaigner Jordi Sanchez wrote on Twitter.
Catalan authorities planned more than 2,300 polling stations for some 5.3 million eligible voters, called to cast ballots from 9 a.m. to 8 p.m. (0700-1800 GMT).
The Spanish government, enforcing a constitutional Court ban on the ballot, said late Saturday that police had shut down "the majority" of designated referendum sites, and had raided the hall where votes were due to be counted.
In recent days the central authorities have seized at least 12 million ballot papers, and millions of posters and leaflets; many websites have also been blocked.
Catalonian government speaker Jordi Turull said Sunday that given the difficulties faced by voters, they could cast their ballot at any open polling station they could find.
Catalonia has 7.5 million inhabitants and, accounting for roughly 20 percent of Spain's economic output, it is one of its wealthiest regions. It has a separate language, Catalan, a history of oppression from Madrid, and grievances about subsidizing the rest of Spain.
According to opinion polls, there is no majority support for independence among Catalans, but the 'yes' vote is widely expected to prevail Sunday as unionists have been urged to boycott the referendum.
Turnout is seen as critical: a high number would allow secessionists to claim they have a mandate for independence; a low one could seriously undermine their attempts to be taken seriously. But there are doubts that participation rates can be measured reliably.
