MADRID/BARCELONA (Reuters) - Spain’s Supreme Court on Monday jailed nine Catalan separatist leaders for between nine and 13 years for their role in a failed independence bid, a decision that triggered mass protests in the region and left the future course of the dispute uncertain.

Barcelona’s international airport became the focal point of the protests. As thousands rallied at its entrance, riot police charged at the crowd on several occasions using batons and firing foam balls to prevent the risk of a forced mass entry, police said. At least three people were arrested in the region.

The Tsunami Democratic group which had called the protest promised a series of coordinated actions to follow.

“We rest to return to the streets tomorrow. And the next day,” it said in a tweet, condemning the use of force by police against what it said was a “non-violent mobilization”.

Local media cited health services as saying over 50 people required medical attention after the clashes.

The airport chaos saw over 100 flights canceled and others delayed, with tourists forced to make their way with heavy luggage through rows of protesters and police.

Protesters in the separatist stronghold of Girona burned tyres on the train tracks, shutting the high-speed connection between Barcelona and France. Regional railways and roads were blocked at several places in the northeastern region.

Earlier, acting Prime Minister Pedro Sanchez said the sentence signified the defeat of the independence movement, whose campaign has caused Spain’s most serious political crisis since the death of dictator Francisco Franco four decades ago.

A government source told Reuters the situation would likely remain risky at least until the weekend.

The strength of the protests could be the first indication of how the future looks for the independence struggle, which has so far been largely peaceful. Nor does the ruling answer the question of how to handle the separatism drive supported by nearly half of Catalonia’s population.

“Today we are all convicted, not just 12 people,” said the president of the Catalan parliament, Roger Torrent.

Former coach of the Barcelona soccer club Pep Guardiola, a cult figure in Catalonia who now manages the Manchester City club, said in a video “the sentence is a direct attack on human rights”, urging “a political and democratic solution”.

The case concerned an independence referendum that was held in October 2017 despite being ruled illegal by Spanish courts, and the subsequent short-lived declaration of independence.

The longest prison term - 13 years - was imposed on the Catalan government’s former deputy leader, Oriol Junqueras. The court convicted him and eight other leaders on charges of sedition and four of them of misuse of public funds.

Three other defendants were found guilty of disobedience and not sentenced to prison. All defendants were acquitted of the gravest charge, rebellion.

“What happened on October 1 (in 2017) was not just a demonstration or a massive act of citizen protest,” the Madrid court said in its ruling. “It was a tumultuous uprising encouraged by the accused, among many others.”

Cabinet spokeswoman Isabel Celaa said the government hoped first of all to promote understanding within the region, saying: “Catalonia must start a dialogue with Catalonia. ... This is precisely the basis for a co-existence,” she said.

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An opinion poll in July showed 48.3% of Catalans against secession and 44% in favor.

‘RISE UP’

The jailed men sent out messages of defiance, urging people to take to the streets.

The CDR grassroots movement said on social media: “It’s time to rise up against the authoritarian fascism of the Spanish state and its accomplices.”

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In Barcelona, protesters holding signs calling for “Freedom for political prisoners” blocked various main streets. A crowd chanted: “We’ll do it again” - a slogan used by separatist supporters who want to hold another referendum.

After dark, several thousand people protested in front of the heavily secured Spanish police headquarters, prompting several police charges to push them back.

The ruling is also likely to color a national election on Nov. 10, Spain’s fourth in four years..

The jailed separatists said via social media they would carry on their fight.

“Nine years in prison won’t end my optimism. Catalonia will be independent if we persist. Let us demonstrate without fear, let us move forward determinedly from non-violence to freedom,” said Jordi Sanchez, former leader of the Catalan National Assembly movement.

Regional leader Quim Torra called for an amnesty for all those sentenced, but Sanchez said the sentences must be carried out, although he also suggested dialogue.

Some in Catalonia said they no longer believed in that.

“We had hope for dialogue, but the state is not up for dialogue. The sentence is very unfair, it’s a great shame and very poor democracy,” civil servant Angels Uibal said.

The court also issued an European arrest warrant for Carles Puigdemont, who was regional leader during its independence bid. He now lives in self-imposed exile in Belgium. In July 2018, the Spanish court dropped a warrant after Germany refused to extradite him.