Spain's government "will oppose all forms of violence", Prime Minister Pedro Sanchez said Friday following the third night of violent protests over the jailing of a rapper for controversial tweets.
"Democracy never, ever justifies violence," said the Socialist leader in his first public condemnation of the unrest which has been applauded by his junior coalition partners, hard-left party Podemos.
Spain's conservative opposition has lambasted the premier for not publicly condemning the violent protests and called for him to break with Podemos over the party's support for the demonstrators.
Angry demonstrations first erupted on Tuesday night after police detained Pablo Hasel, 32, who was holed up in a university in Catalonia to avoid going to jail in a case which has raised concerns about free speech in Spain.
About 100 people have been arrested since the protests began, including 16 overnight in Barcelona and the eastern city of Valencia, and dozens of people have been injured, according to local authorities.
Among them is a young woman who lost an eye on Tuesday night in Barcelona after being hit by a foam round fired by police to dispel demonstrators.
Protesters have thrown rocks and other objects at police, set up barricades with garbage containers and torched street furniture.
The protests began in Catalonia, where the rapper is from, but have spread to other cities including Madrid where another demonstration is planned for Saturday.
While the clashes were raging in Madrid and Barcelona on Wednesday night, Podemos MP Pablo Echenique publicly tweeted his backing for the protesters.
"All my support to the young anti-fascists who are demanding justice and freedom of expression in the streets," he wrote.
And Podemos leader Pablo Iglesias, who is also a deputy prime minister, has said Hasel's jailing backs his argument that Spain lacks "democratic normality".
Hasel, known for his hard-left views, was arrested after failing to turn himself in last 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.
Catalan students unions have called for a strike and a protest on Friday over the arrest of the rapper.