The protest turned violent after protesters set garbage containers and cardboard on fire in the middle of central Barcelona streets, including next to high-end commercial streets home to many of the city's designer stores, according to a Reuters witness.
A spokesman for the regional Mossos police said three people had been detained near the local headquarters of the Spanish government, where police charged into the crowd with batons to try to gain space after there were problems with police fences.
Thirteen people have suffered minor injuries after clashes broke out between police and protesters in Spain's Catalonia region earlier on Monday, following the Spanish Supreme Court’s sentencing of pro-independence leaders.
Earlier in October, the Supreme Court ruled on the cases of 12 politicians who were involved in organising the October 2017 referendum, which Madrid called illegal, handing out prison terms ranging from nine to 13 years. Thousands of protesters took to the streets throughout the country after the decisions were announced, which soon escalated to violent clashes with police. A total of 131 people have been reportedly injured in the clashes so far.