Spanish police arrested 128 people during a night of looting, vandalism and violent unrest in Barcelona, authorities announced Sunday, as a wave of youth-led protests continued to sweep across European cities. Meanwhile, Italian police detained a 30-year-old pro-Palestinian activist suspected of encouraging further unrest through social media, with local reports revealing his history of praising Hamas' October 7 attack on Israel.
The disturbances in Barcelona began Saturday evening, when hundreds of young people gathered around Plaça de Catalunya, one of the city's busiest central squares, following calls circulated on social media. The gathering had not been authorized by local authorities and quickly descended into violence.
Masked rioters kick in store windows and loot merchandise in central Barcelona
Video footage shared online showed groups of young people, many dressed entirely in black and wearing masks, running through the streets, smashing store windows and carrying away stolen merchandise. Clothing, footwear and electronics stores were among the businesses targeted.
According to the Catalan regional police, known as the Mossos d'Esquadra, 23 businesses were vandalized or looted, while firefighters responded to 33 fires involving street furniture, garbage containers and other property.
More than half of those arrested were minors, according to authorities. Catalan police chief Sílvia Catà said 73 detainees were under 18, while other police summaries put the figure at 72. Only two of those arrested had previous records for public disorder offenses. Fifteen police officers were injured during the disturbances, four of them seriously.
Some of the most alarming scenes unfolded inside shopping establishments. Videos showed customers trapped inside stores, including the El Corte Inglés department store, after security shutters were lowered to prevent looters from entering.
Other footage showed masked rioters kicking through shop windows before fleeing with merchandise. In several cases, participants broadcast their actions live on social media, where viewers could be seen encouraging them.
Barcelona Mayor Jaume Collboni condemned the violence and warned that those responsible would face legal consequences, including potential action against the guardians of minors involved.
Fifteen police officers were injured during the unrest, four of them seriously
Police detain a participant in the riots, which were organized through social media
Catà described the disturbances as violence for its own sake, saying investigators were working to establish the backgrounds of those detained and determine how the unrest had been organized.
Although the participants did not appear to belong to a single organization, police said they had coordinated their activities through social media. Online posts encouraged young people to join an anti-establishment movement, sometimes using the slogan Instituts Indignats, a reference to the French Lycéens Indignés, or "Angry High School Students," movement that has mobilized demonstrators in France in recent weeks.
The incidents come amid a broader wave of demonstrations across Europe, although the protests have varied significantly in their demands and levels of violence.
Soldiers deployed in Milan, protesters enter Rome's Colosseum
Italy has become another focal point of the unrest, particularly Milan, where violent clashes and looting the previous weekend involved approximately 2,000 young demonstrators, according to police. Many were teenagers from working-class suburbs, including children of immigrant families.
Protesters march through Rome on Saturday
(Photo: AP Photo/Gregorio Borgia)
(Photo: AP Photo/Gregorio Borgia)
Demonstrators wave Palestinian flags during a protest in Milan
(Photo: AP Photo/Antonio Calanni)
Italian authorities responded to fears of renewed violence Saturday by deploying large numbers of police officers and soldiers to major cities.
In Milan, Prime Minister Giorgia Meloni's government sent an additional 500 soldiers to reinforce the security presence, alongside thousands of police and other law enforcement personnel. Authorities also conducted preventive checks and tightened security around transport hubs and shopping districts.
Businesses prepared for the worst. Luxury retailers in Milan's famous fashion district, including Omega, Tiffany and Gucci, covered their windows with wooden boards to protect them from potential attacks.
Thousands of demonstrators nevertheless gathered in the city, chanting slogans against Meloni and displaying banners reading "No to the lies of the state." One group dumped waste outside the offices of Italy's energy regulator and burned a symbolic oversized electricity bill in protest against rising costs.
Despite fears of another violent outbreak, the main demonstration in Milan ended largely peacefully, in contrast to the previous weekend's destruction. A separate group of about 30 far-right activists, described as soccer hooligans associated with Inter Milan, appeared briefly and shouted anti-immigrant and anti-Muslim slogans before being isolated by police.
Police use water cannons and tear gas during clashes with protesters in Rome
(Photo: AP Photo/Gregorio Borgia)
(Photo: AP Photo/Antonio Calanni)
Shops in Milan's luxury shopping district board up their windows ahead of demonstrations
(Photo: AP Photo/Antonio Calanni)
Rome also saw heightened security, with authorities restricting access to luxury shopping streets and major landmarks. A small group of protesters attempted to force its way into the Colosseum, and some entered the ancient amphitheater before being escorted out by security personnel.
Elsewhere in the capital, an anti-war march turned tense despite organizers' efforts to prevent violence. Participants had been urged to keep their faces uncovered and their hands visible to demonstrate that they had no intention of attacking police.
Nevertheless, brief confrontations broke out near Piazza della Repubblica, where officers used batons, tear gas and water cannons to disperse demonstrators. Similar tensions were reported in other Italian cities, including Turin, as protests continued over economic hardship, government policies and international conflicts.
The Moroccan-origin activist suspected of inciting unrest
As Italian authorities investigated the violence in Milan, attention turned to Youssef Siher, a 30-year-old Italian citizen of Moroccan descent who had become prominent in pro-Palestinian activist circles.
Police detained Siher on Saturday following an investigation into a social media movement called Movimento 17 ottobre, or "October 17 Movement," which promoted demonstrations across several Italian cities.
According to Italian reports, Siher created an Instagram page and Telegram group after the initial outbreak of violence in Milan, using the platforms to encourage further demonstrations and urge followers to take control of public squares.
Youssef Siher
Investigators suspect that the online campaign sought to capitalize on anger among young Italians, particularly those from immigrant backgrounds, toward the authorities.
Following searches of properties associated with Siher, investigators reportedly recovered electronic files containing proposed gathering points and organizational details for demonstrations planned for Saturday. At least one of those locations was subsequently used by pro-Palestinian protesters.
Siher was detained on orders from Milan prosecutors and is under investigation for alleged criminal incitement, organized violence at public demonstrations and terrorism-related offenses. He has not been convicted. Italian authorities also placed his wife under investigation in connection with the same alleged offenses, although she remained free.
There is an important distinction between the allegations against Siher and his possible responsibility for the earlier unrest. His online movement emerged after the initial disturbances in Milan, and Italian reporting has cautioned that investigators have not established whether he exercised actual command over the original rioters.
The investigation has nevertheless brought renewed scrutiny to Siher's background and his previous activities.
Siher, who grew up in the Brescia area in northern Italy, pursued higher education in communications and political science at the University of Milan. He also studied political Islam, Middle Eastern politics and geopolitical affairs.
His academic background included research experience at the Italian Institute for International Political Studies, known as ISPI. He also worked as a freelance journalist, contributing to Italian publications including Il Fatto Quotidiano and Il Foglio. Although he had no previous criminal record, Siher had become increasingly active in pro-Palestinian organizations and demonstrations in Italy.
According to Corriere della Sera, Italian intelligence agencies had taken an interest in him in 2024 after he established an organization called Alba Nascente, or "Rising Dawn." The group reportedly promoted demonstrations against Israel and disseminated material sympathetic to Hamas and the Popular Front for the Liberation of Palestine.
Youssef Siher, the Italian pro-Palestinian activist detained on suspicion of incitement in connection with the October 17 Movement
Italian media also reported that Siher had collaborated with a satellite television channel described as close to Hezbollah. The nature and extent of that alleged relationship have not been independently established.
His past statements about the October 7, 2023, Hamas attack on Israel have attracted particular attention. On the day of the attack, Siher responded to a social media message by Italian Deputy Prime Minister Matteo Salvini expressing solidarity with Israel by writing "Allahu Akbar," meaning "God is greatest."
In a subsequent article published by the online magazine Miccia, Siher argued that few people in the West had understood the true meaning of Hamas' October 7 operation, known by the organization as Al-Aqsa Flood.
He described it as "a revolutionary act of decolonization," portraying the assault through an ideological framework of resistance to colonialism. The statement has since resurfaced in Italian media coverage of his detention.
Siher continued publishing criticism of Israel and the Italian government in recent months. In some writings, he sought to connect separate incidents involving the deaths of young men from immigrant backgrounds during encounters with law enforcement, presenting them as examples of wider institutional discrimination.
Investigators are now examining whether his online activity went beyond political advocacy and crossed the legal threshold into criminal incitement or the organization of violence.
The case comes as European authorities confront the growing role of social media in mobilizing demonstrations, including gatherings that begin with political demands but escalate into coordinated attacks on property and confrontations with police.