More than half a million people rallied in Barcelona on Friday in protest at Spain's sentencing of nine separatist leaders to long prison terms over an abortive independence bid, local police said. Figures provided by the police said some 525,000 people had joined the demonstration, which saw many thousands of people arriving in the city after taking part in a three-day walk from five towns in the region. A crowd of protesters hurled stones and cans at police in riot gear, and dragged large garbage bins to the middle of a main city boulevard, and set them ablaze. Police vans tried but failed to push people back onto the pavements. Dumpsters burn during Catalonia's general strike in Barcelona, Spain, October 18, 2019 (Photo: Reuters) Other mass rallies held across the city to denounce lengthy prison terms handed down this week to nine independence leaders, were peaceful. "Throughout this week, as you well know, there have been violent incidents in Catalonia. They have been organised ... by groups who are a minority but are very organised," Interior Minister Fernando Grande-Marlaska told a news conference. "Their actions, as we have already said, will also not go unpunished." "We have always been peaceful people, but you get to a point where you get treated in such a way that people are getting angry," said Carlota Llacuna, a 19-year old student from the Maresca region near Barcelona. "They put our leaders in prison." One of the main ringleaders, Catalonia's former chief Carles Puigdemont, has so far escaped trial after he fled to Belgium in 2017 when the independence drive was thwarted. Spain this week renewed its bid to get him extradited and he was briefly detained by Belgian police on Friday before a judge ordered his release pending a decision on the Spanish arrest warrant. A court is meant to hear the case on Oct. 29. El Clasico Postponed Several main streets in Barcelona were closed to traffic because of Friday's marches, while regional trains and the city's metro were running on a reduced timetable. Barcelona's main landmark, the multi-spired Sagrada Familia cathedral designed by Antoni Gaudi, was closed due to the protests, an official told Reuters. The Spanish soccer federation (RFEF) said in a statement on that Barcelona's Oct. 26 home match against Real Madrid, which is known as "el clasico" and is one of the biggest rivalries in world sport, had been postponed due to security concerns. Barcelona's El Prat airport cancelled 57 flights on Friday, airport operator Aena said. Barcelona town hall said 700 garbage containers had been set ablaze since protests began on Monday and estimated that the city had suffered damage totalling more than 1.5 million euros ($1.67 million). Riot police stand guard as a dumpster burns during Catalonia's general strike in Barcelona, Spain, October 18, 2019 (Photo: Reuters) In an apparent effort to hamper the protesters, a Spanish judge ordered on Friday the closure of web pages linked to a pro-independence group, Democratic Tsunami, which has been deftly directing its followers to various demonstrations. However, as soon as its site was shuttered, the group migrated its homepage to a new url, sidestepping the ruling. Democratic Tsunami is a new, secretive group that emerged in September and has drawn thousands of followers on both its website and social media. Although it says it is committed to non-violent protests, many young demonstrators have battled police over the past three nights in Barcelona in scenes reminiscent of the some of the urban unrest that has rocked France over the past year. Regional police said 16 people were arrested across Catalonia on Thursday, while health officials said 42 people needed medical attention. *This story was compiled by Ahram Online