At least 128 people have been arrested in Barcelona, Spain, after a youth protest descended into looting, vandalism and violent clashes with police, leaving 15 officers injured and several businesses damaged.

Catalan police chief Silvia Cata said on Sunday that 73 of those arrested were minors, whose cases would be referred to the juvenile prosecutor’s office.

The violence broke out late on Saturday around Plaça de Catalunya, a busy square in central Barcelona, after a gathering promoted on social media attracted about 600 people, according to Spanish media reports.

The protest was promoted under the slogan “Instituts Indignats”, drawing inspiration from the French youth movement “Lycéens Indignés”, which has organised demonstrations in France.

The gathering deteriorated as groups of young people allegedly attacked businesses, smashed shop windows and removed goods from stores.

Footage circulated on social media showed demonstrators setting objects on fire and damaging commercial properties. Protesters also reportedly threw stones and other heavy objects at police officers, erected barricades and set rubbish bins alight.

Police moved in to disperse the crowd, triggering confrontations that spread into nearby streets. Motorcycles, bicycles and bus shelters were also damaged during the unrest.

Reports by Spanish media indicated that about 14 shops were looted, while the wider assessment of damage included additional businesses vandalised during the disturbances.

The violence forced several businesses to close as authorities restricted access to Plaça de Catalunya. Train services at the square’s station were also temporarily suspended as security operations continued.

Cata described the incidents as “gratuitous violence” and said the gathering was largely disorganised, despite calls for participation spreading through social media. She added that only two of those arrested had previous criminal records.

Barcelona Mayor Jaume Collboni condemned the destruction and said the city council would participate in legal proceedings to ensure those responsible were held accountable.

He assured that the authorities would pursue the matter fully, including possible consequences for the parents or legal guardians of minors involved in the unrest.

Salvador Illa, president of the Catalan government, also condemned the violence while defending the police response. He maintained that citizens had the right to protest but could not use that right to justify attacks or destruction of property.

Catalonia’s interior minister, Núria Parlon, similarly described the incidents as vandalism and rejected any suggestion that the violence represented a legitimate cause.

Authorities also sought to distinguish the unrest from a housing-rights encampment that has occupied part of Plaça de Catalunya for several weeks.

Police said investigations were continuing into those detained and the circumstances surrounding the disturbances, while the Barcelona city council prepared to pursue legal action over the damage.