Thousands have protested in Rio de Janeiro to support teachers seeking pay hikes. However, demonstrations turned violent when masked anarchists began setting fires and breaking into buildings.
The demonstration Monday started out peaceful in Brazil's Rio de Janeiro but, once night fell, violence broke out.
At least 200 "black bloc" anarchists smashed a city hall gate, while others broke into banks and tried to break open ATMs, setting some of them on fire.
The masked group also pulled furniture out of banks to use in barricades as they squared off with police, who used tear gas against the crowd.
A rally in Sao Paulo also turned violent with a car that had been set alight exploding near protestors. Seven people were injured in protests there, including four police officers, the newspaper O Estado de Sao Paulo reported.
Teachers who have been pressing for a pay raise for two months union groups said 50,000 people marched to support them it turned violent. Police said only 10,000 people had rallied.
Brazil's security situation is an ongoing challenge as the city prepares to host the 2014 World Cup and 2016 Olympic Games.
hc/rc (AFP, dpa)