Update 10.03pm: Catalonia "has won the right to become an independent state", the Spanish region's leader Carles Puigdemont said.
Speaking on television from Barcelona after polling stations had closed, Mr Puigdemont said "today the Spanish state wrote another shameful page in its history with Catalonia".
Spanish riot police smashed their way into polling stations across Catalonia to try and stop Sunday's referendum on independence, sometimes beating and kicking voters.
Catalan president Carles Puigemont: "Catalans have earned the right to an independent state. Catalonia has won its sovereignty"— Catalan News (@catalannews) October 1, 2017
Spain's top court had suspended the vote but local authorities went ahead anyway.
Update 9.57pm: The main grassroots separatist group in Catalonia is urging the regional government to declare independence from Spain after the violent police crackdown on Sunday's independence referendum.
Jordi Sanchez, leader of secessionist group ANC, told a large crowd in Barcelona's main square he hopes that "very soon we will see the birth of a new Catalan state".
President @KRLS: "To you and to all those who today have made this democratic victory possible, all who have expressed their support,"— Catalan Government (@catalangov) October 1, 2017
Mr Sanchez warned local leaders: "Now, don't let us down. The moment of truth has arrived."
Catalan president Carles Puigdemont had vowed to declare independence with 48 hours if the Yes side wins Sunday's disputed vote.
But there was no campaign for the No side before the vote was suspended by Spain's Constitutional Court.
Authorities said 844 people and 33 police were injured Sunday in Spanish police raids to halt the vote.
Update 4.45pm: More than 460 people have been injured in Catalonia in clashes with Spanish police trying to prevent a referendum on independence from taking place in the northeastern region, Barcelona's mayor Ada Colau said.
Ms Colau said today, as mayor of the city, she demands "an immediate end to police charges against the defenceless population".
Police have baton-charged and fired rubber bullets to disperse crowds in Barcelona and other towns and cities.
Videos have showed them beating people repeatedly as they try to confiscate ballots and ballot boxes.
In addition to the protesters and voters injured, Spain's Interior Ministry said 11 police officers have been injured fulfilling judicial orders to prevent the referendum on independence.
Earlier Catalan government spokesman Jordi Turull blamed the violence directly on Spanish prime minister Mariano Rajoy and interior minister Juan Ignacio Zoido.
He said actions by Spanish National Police and Civil Guard forces on Sunday were politically motivated and showed "a clear motivation to harm citizens".
Update 2.55pm: Barcelona have announced their La Liga match against Las Palmas will be played behind closed doors today after league officials refused to postpone the fixture.
Update 1:52pm: Catalonia's government spokesman said 337 people have been injured, some seriously, in the Spanish police crackdown on the independence referendum.
Catalan Minister for Foreign Affairs said Raül Romeva i Rueda: "We have initiated contacts with the EU about the violation of fundamental rights that puts the very same EU at risk."
"We urge Europe's institutions to condemn the violence that European citizens are suffering," he added.
Catalan spokesperson Jordi Turull i Negre said: "The person responsible is Mariono Rajoy."
Update 11am: Catalonia's emergency services say 38 people have been injured in clashes with Spanish police during today's indepenence vote.
Spanish police have fired rubber bullets into crowds of people in Barcelona as they try to stop voting in Catalonia's banned independence referendum.
It happened during a seemingly peaceful sit-down protest in the city.
Mr Puigdemont condemned the crackdown. "Police brutality will shame forever the Spanish state," he said as crowds cheered.
But Enric Millo, the Spanish government's representative in the region, said police and National Guard forces acted "professionally" to enforce court orders. He said any attempt to claim the referendum as valid is doomed.
"Today's events in Catalonia can never be portrayed as a referendum or anything similar," he said.
Update 10.11am: Spanish police have fired rubber projectiles at protesters outside a Barcelona polling station.
Catalonia’s emergency services have treated 38 people who have been injured as a result of the repression by Spanish police— Catalan Government (@catalangov) October 1, 2017
La poli surt disparant pic.twitter.com/4RyFWkaq3X— Jordi Graupera (@JordiGraupera) October 1, 2017
Update 9am: Spanish riot police have smashed their way into a polling station in Catalonia where the regional leader was expected to vote in the disputed independence referendum.
Civil Guard riot police with shields used a hammer to smash the glass of the front door of the voting centre and lock cutters to force their way in.
Scuffles erupted outside between police and people waiting to vote at the centre in Sant Julia de Ramis, near the Catalan city of Girona.
Television footage showed police using batons to disperse the crowds gathered outside the local sports centre.
Catalan president Carles Puigdemont had been scheduled to vote there this morning. He has spearheaded the separatist politicians' push to go ahead with the vote, despite a Constitutional Court suspension and fierce opposition by central authorities.
Spanish Police are also seizing ballot boxes from some Catalan polling stations. Videos shows police in riot gear removing the boxes as thousands of people prepared to vote in Catalonia's referendum on independence.
At least one woman was injured outside the building and wheeled away on a stretcher by paramedics.
Polling station workers inside the building reacted peacefully and broke out into songs and chants challenging the officers' presence.
National Police and Civil Guard officers also showed up in other polling centres where Catalan officials were expected.
Catalans defied rain and police orders to visit designated polling stations for the banned referendum on the region's secession that has challenged Spain's political and institutional order.
Reporters saw ballot boxes wrapped in plastic bags being carried into some of the polling stations in Barcelona occupied by parents, children and activists before some polling stations opened.
The plastic ballot boxes, bearing the seal of the Catalan regional government, were placed on tables, prompting the cheering of hopeful voters that had gathered in schools before dawn.
Some 2,300 facilities had been designated as polling stations, but it was unclear how many were able to open. The Ministry of Interior did not provide a number late on Saturday when it said that "most" of them had been sealed off and that only "some" remained occupied.
Police have received orders to avoid the use of force and only have been warning people to vacate the facilities. They are also supposed to confiscate ballots and ballot boxes.
In an effort to overcome myriad obstacles, Catalan officials announced that voters would be allowed to cast ballots in any location and using ballots printed at home, rather than in designated polling stations as previously announced.
Regional government spokesman Jordi Turull also said that a group of "academics and professionals" would serve as election observers. The official electoral board appointed by the regional parliament was disbanded last week to avoid hefty fines by Spain's Constitutional Court.
"We are under conditions to be able to celebrate a self-determination referendum with guarantees," Mr Turull said in a press conference. "Our goal is that all Catalans can vote."
Tension has been on the rise since the vote was called in early September, crystalising years of defiance by separatists in the affluent region.
Spain's 2008-2013 financial crisis and harsh austerity measures fuelled frustration in Catalonia for setbacks in efforts to gain greater autonomy, with many Catalans feeling they could do better on their own.
Courts and police have been cracking down for days to halt the vote, confiscating 10 million paper ballots and arresting key officials involved in the preparations. On Saturday, Civil Guard agents dismantled the technology to connect voting stations, count the votes and vote online, leading the Spanish government to announce that holding the referendum would be "impossible".
Joaquim Bosch, a 73-year-old retiree at Princep de Viana high school, where a crowd of 20 people was growing on Sunday morning, said he was uneasy about a possible police response to the crowds.
"I have come to vote to defend the rights of my country, which is Catalonia," Mr Bosch said. "I vote because of the mistreatment of Catalonia by Spain for many years."
On Saturday, Spain's foreign minister dismissed the planned vote as anti-democratic, saying it runs "counter to the goals and ideals" of the European Union.
"What they are pushing is not democracy. It is a mockery of democracy, a travesty of democracy," Alfonso Dastis said.
Polls have opened in a banned referendum on Catalonia's independence, with the first voters casting ballots amid cheers in some of the designated polling stations.
Parents, children and activists had occupied some of the 2,315 schools and other facilities to avoid them being closed by police acting on court orders.
Spain's Constitutional Court ordered the vote to be suspended and central authorities say it is illegal.
Regional separatist leaders have 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.