Spanish police and protesters clashed for a third night on Thursday over the jailing of a rapper for controversial tweets. Dozens of people were arrested since Tuesday night when protests erupted after police detained Pablo Hasel, 32, who had taken refuge in a university in Catalonia to avoid going to jail in a highly contentious free-speech case. The violence thrusts the hard-left Podemos party – the junior partner in Spain's left-wing coalition which has opposed Hasel's jailing and publicly supported the protesters – into the firing line. Police fired tear gas and reported six arrests in Barcelona on Thursday after protesters set up barricades. The centre of the Catalan capital was filled with burning rubbish bins and furniture. Hooded youths hurled stones and bottles at police vans and damaged some vehicles. The newsroom of the newspaper <em>El Periodico de Cataluna</em> was attacked, while TVE television showed images of clashes in the eastern city of Valencia. On Wednesday night, hundreds of people gathered in Madrid's Puerta del Sol square calling for Hasel's release, hurling bottles at police, who charged at them in clashes lasting several hours. Police arrested 19 people, while the city's emergency services said 55 people were injured, among them 35 police officers. In Barcelona and three other Catalan cities, demonstrators threw objects at police and set barricades on fire on Wednesday, with police charging the protesters and firing foam rounds. Across the country aout 50 people were arrested. The director of Catalonia's regional police force, Pere Ferrer, said officers faced a "highly complex scenario" because of the "high volume of public disorder", which included looting. The force opened an investigation after a young woman in Barcelona lost an eye on Tuesday night after being hit by a foam round, he said. Hasel, known for his hard-left views, was arrested after failing to turn himself in on Friday to start a nine-month sentence over tweets calling former king Juan Carlos I a mafia boss and accusing police of torturing and killing demonstrators and migrants. A court in his hometown of Lerida on February 12 sentenced the rapper to another jail term of two and a half years for threatening to kill a man at a bar, according to a ruling published on Thursday. Hundreds of artists rallied to Hasel's cause, including filmmaker Pedro Almodovar and Hollywood actor Javier Bardem. Amnesty International said jailing him for song lyrics and tweets was "unjust and disproportionate" while campaigners say prosecuting him is a dangerous assault on free speech. The violence was denounced by figures across the political spectrum with Socialist deputy prime minister Carmen Calvo saying it was indefensible. "No right can be defended or expressed with violence. That is an absolute red line," Ms Calvo told RTVE public television. So far, Prime Minister Pedro Sanchez has stayed silent on the Hasel case and the protests, which have highlighted a growing divide between his Socialists and Podemos, which emerged out of the anti-austerity "Indignados" movement that occupied squares across Spain in 2011. In the immediate firing line was Podemos MP Pablo Echenique, who publicly tweeted his backing for the protesters as the clashes were raging. "All my support to the young anti-fascists who are demanding justice and freedom of expression in the streets," he wrote. But much anger was directed at Podemos leader Pablo Iglesias, also a deputy prime minister, who criticised Hasel's jailing and used it to question Spain's democracy. "They have to remove Pablo Iglesias from the Spanish government. It is the only way to turn away from this dangerous path we're going down," said Cuca Gamarra, spokeswoman for the opposition Popular Party's parliamentary faction. The Socialist Party "cannot be complicit in the face of what's going on ... and this display of 'Trumpism' we're seeing from Podemos' leaders," she told RTVE, referring to former US president Donald Trump's attempt to incite supporters to storm the Capitol in Washington last month.