Thousands rally in Catalonia against referendum violence

"This was the norm under Franco!" the crowd chanted as they made their way through the streets of Barcelona, referring to Spain's former dictator Francisco Franco whose 1939-75 regime repressed Catalan language and culture.

About 15,000 people took part in the protest in Barcelona, the capital of Catalonia, according to municipal police.

They waved blue, red and yellow Catalan independence flags and held up signs demanding more democracy.

Riot police moved in on polling stations in towns and cities across the region on Sunday to stop people from voting in the referendum deemed unconstitutional by the Spanish courts, in some cases baton-charging and firing rubber bullets to disperse crowds.

Four people were hospitalised, two in serious condition -- a 70-year-old man had a heart attack and another was hurt in his eye.

"I saw my father dragged away, saw my dance teacher get punched and headbutted. They threatened to break our fingers if we didn't come down from a fence," one of the demonstrators, 19-year-old Patricia Ventura, told AFP.

"I can't remove these images from my head, nobody could make me forget them."

Shocking videos posted on social media showed police dragging voters from polling stations by their hair, throwing people down stairs and attacking Catalan firefighters protecting polling stations.

"I know so many people that are not pro-independence and yesterday they hit the streets because they were outraged," said another demonstrator, Blanca Pi.

Catalan president Carles Puigdemont and Barcelona mayor Ada Colau took part in another rally that drew hundreds of people.

"What happened yesterday is disgusting, for me it calls for a break (from Spain), I don't see how we can overcome it," said 30-year-old bank employee Helena Vidal, her eyes welling with tears.

Demonstrations were held in several other cities, including Girona, about a hundred kilometres (60 miles) to the north of Barcelona and Lleida, 160 kilometres to the west.