MILAN — Italy sent 500 additional soldiers to Milan on Saturday as thousands of demonstrators took to the streets across the country, a week after young protesters smashed into shops and looted businesses near the city’s central Duomo square. The march in Milan ended peacefully, but police and soldiers maintained a heavy presence. The extra troops joined hundreds already stationed in the city, alongside about 5,000 police and other security personnel. Authorities used drones, railway-station checks and rapid-response units, while many luxury shops boarded up their windows ahead of the march. Premier Giorgia Meloni also announced tougher penalties for minors. Police detained several young people in Milan as a preventive measure. Last weekend’s unrest led to 45 arrests over two days, including 34 minors, according to police figures cited in local media. Saturday’s Milan march included chants directed at Meloni and banners reading “No to lies of the state.” Protesters dumped manure outside Italy’s energy regulator and burned an oversized mock electricity bill, according to images shown on local television. The march concluded peacefully outside Milan Polytechnic, more than three kilometers from the city center. Authorities said they were investigating a 30-year-old freelance journalist suspected of being a leading organizer of the newly formed Oct. 17 movement, which has driven recent protests in Italy. Defense Minister Guido Crosetto said troops could use plastic restraint ties only around railway stations and were not authorized to carry pepper spray or tasers. In Rome, police briefly clashed with demonstrators near Piazza della Repubblica, where an anti-war march turned tense despite organizers’ efforts to hold the crowd back. Police used a water cannon, and the protesters withdrew. A separate group tried to enter the Colosseum but was ushered away by guards. A far-right student association leader, Riccardo Ponzio, condemned last week’s destruction, saying most young people wanted to study and did not want their concerns used to justify wrecking cities. The protests spanned a wide range of issues, including education, corruption, war, pensions and housing. In Albania’s capital, Tirana, riot police used water cannons as demonstrators threw objects and set government buildings on fire. Some students there are demanding lower tuition, increased public investment and action against corruption, while others have joined calls for Socialist Prime Minister Edi Rama to resign. Rama said his government was preparing a response to students’ demands and called for dialogue, warning that violent protesters would face penalties. Thousands of retirees and other demonstrators marched peacefully in Madrid to oppose possible changes to public pensions ahead of next month’s snap election. Protester Maria José Benito, 68, said she feared the system could be privatized. Housing costs have also fueled protests in Spain this fall. In Lisbon, demonstrators demanded more affordable housing and criticized government plans to ease limits on annual rent increases and make it easier to evict tenants who do not pay. Prime Minister Luis Montenegro has defended the changes as a way to build trust between landlords and tenants and encourage rental supply. Protesters say the measures leave renters more exposed. The Italian demonstrations followed violence last weekend in Milan, where about 2,000 young people were involved in unrest, according to police. Saturday’s largely peaceful march was a sharp contrast, though brief clashes in Rome and serious violence in Tirana underscored the challenge facing authorities as protests spread across the region.