Spanish police and protesters clashed for a third night Thursday over the jailing of a rapper for controversial tweets, triggering a political backlash.
Dozens of people have been arrested since Tuesday night when angry demonstrations erupted after police detained Pablo Hasel, 32, who was holed up in a university in Catalonia to avoid going to jail in a highly contentious free speech case.
The violence has thrust the hard left Podemos party -- the junior partner in Spain's leftwing coalition which has opposed Hasel's jailing and publicly supported the protesters -- into the firing line.
Police reported six arrests in Barcelona on Thursday after protesters set up barricades, prompting police to fire tear gas.
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 El Periodico de Cataluna 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, AFP journalists said.
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 lobbed objects at police and set barricades ablaze on Wednesday, with police charging the protesters and in some places firing foam rounds. Some 50 people were arrested across the country.
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 has opened an investigation after a young woman lost an eye on Tuesday night in Barcelona as a result of a foam projectile used by police to dispel the protesters, he added.
- 'Absolute red line' -
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 Thursday.
Hundreds of artists have 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 roundly 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," deputy prime minister Carmen Calvo told RTVE public television.
So far, Prime Minister Pedro Sanchez has remained 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.
- 'Display of Trumpism' -
But much anger was directed at Podemos leader Pablo Iglesias -- also a deputy prime minister -- who has 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," 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 Donald Trump's bid to incite supporters to storm the US Capitol last month.