Barcelona - Spanish riot police smashed their way into polling stations to try to halt a disputed independence referendum on Sunday and fired rubber projectiles at protesters outside a Barcelona polling station. Several people were wounded in the confrontation.The officers fired the projectiles while trying to clear protesters who were trying to impede National Police cars from leaving after police confiscated ballot boxes from the voting centre. The Spanish government has ordered police to stop the voting process, saying it's illegal.An AP photographer saw several people who had been injured during the scuffles outside Barcelona's Rius i Taule school, where some voters had cast ballots before police arrived.Manuel Conedeminas, a 48-year-old IT manager who tried to block police from driving away with the ballot boxes, said agents had kicked them before using their batons and firing the projectiles, which were ball-shaped.Elsewhere, Civil Guard officers, wearing helmets and carrying shields, used a hammer to break the glass of the front door and a lock cutter to break into the Sant Julia de Ramis sports centre near the city of Girona. At least one woman was injured outside the building and wheeled away on a stretcher by paramedics.ClashesClashes broke out less than an hour after polls opened, and not long before Catalonia regional president Carles Puigdemont was expected to turn up to vote at the sports centre. Polling station workers inside the building reacted peacefully and broke out into songs and chants challenging the officers' presence.Puigdemont was forced to vote in Cornella de Terri, near the northern city of Girona, his spokesperson Joan Maria Pique told The Associated Press.The Spanish government and its security forces are trying to prevent voting in the independence referendum, which is backed by Catalan regional authorities. Spanish officials had said force wouldn't be used, but that voting wouldn't be allowed.Spain's Constitutional Court has suspended the vote. Regional separatist leaders pledged to hold it anyway, promising to declare independence if the "yes" side wins, and have called on 5.3 million eligible voters to cast ballots.Police had sealed off many voting centres in the hours before the vote to prevent their use. Others were filled with activists determined to hold their ground.Puigdemont has spearheaded the separatist push to go ahead with the vote, despite a Constitutional Court suspension and fierce opposition by central authorities.