Barcelona (AFP) - "I feel fury and a sense of powerlessness," said Joan Guich, one of thousands of people who took to the streets of Barcelona after Spain's Supreme Court jailed nine Catalan leaders over a failed independence bid.
"They have been convicted for an ideology which I agree with," said this 19-year-old student, who gave voice to a sentiment felt by many.
For supporters of Catalan independence, Monday's verdict, which saw their leaders handed heavy prison terms, was like a red rag to a bull.
And the anger was palpable: in their thousands, they blocked access to Barcelona airport, they brought train lines grinding to a halt and blocked roads in the city and across the region, in some places even engaging in running battles with the police.
"We are going to make ourselves heard, they should know that this is not over," said Jordi, 44-year-old shopkeeper.
"Until now, we have been waiting to see what would happen with the sentence. And the Spanish state, as ever, does not disappoint."
Worst hit was the airport, where under a light drizzle, hundreds of protesters hurled stones, rubbish bins, plastic bottles and other objects at the police.
The police responded by repeatedly charging them and firing rounds of foam bullets into the crowd, and the regional emergency services said they treated 53 people for injuries.
"We have always chosen peaceful ways (of fighting for what we believe in) but nobody listens. Now we are forced to go down the route of civil disobedience," said Carles Navarro, a 49-year-old IT consultant.
"The indignation is just too much and affects too many people. What they don't realise is that we are very angry and we will not stop."
Although the sentence was widely expected to be harsh, it still caused a lot of anguish among pro-independence supporters who within minutes had begun to fill the streets of Barcelona.
"Today is going to be historic, you can feel it in the atmosphere. Serious things are happening, we can't stay home," said Oscar Quiles, a 47-year-old real estate entrepreneur and one of some 25,000 people who by 1:00 pm (1100 GMT) had packed into Plaza Catalunya in the centre of Barcelona.
"People are really wound up," he warned.
The tension had been palpable since the early morning as the city awoke to a helicopter flying overhead and heavy police presence in potential flashpoint areas around the court, the main train station and the airport.
But focus quickly turned to Barcelona's El Prat airport with supporters directed there by a group called Democratic Tsunami which has more than 150,000 followers on Telegram.
"The time has come to make our voice felt around the world. The goal: stop the activity of Barcelona's airport," the group said in a message to supporters.
Thousands of them went on foot, or by metro, taxi, train or car to the airport where they paralysed transport links although a major police presence stopped them from entering the terminal itself.
A huge tailback of hundreds of stationary cars could be seen on the road leading to the airport, with some people getting out to finish the journey on foot. And arrival passengers were also stranded, with no taxis and trains and metro only working intermittently.
According to the AENA airports operator, at least 110 flights were cancelled.
In Girona, about 100 kilometres (60 miles) north of Barcelona, demonstrators also managed to block the high-speed train line from France.
- 'Weeks of mobilisation' -
In the evening, the Catalan National Assembly (ANC) and Omnium Cultural, the region's two biggest grassroots pro-independence groups, also called supporters to a rally. The two groups were responsible for organising some of the largest separatist protests in recent years.
The coming days look set to be equally unsettled.
From Wednesday, separatist groups have called for marches throughout the region that will converge in Barcelona on Friday, when unions have called a general strike.
And student groups have pledged to begin their own strike on Wednesday.
"The only way left for us is disobedience. This week will be all about mobilisation and it will go on for a long time," said Juli Cuellar, a 44-year-old office worker.