Demonstrations turned violent Tuesday night in Sao Paulo as protesters, many of them university students, turned out to support teachers on strike for higher wages.
Police reported that four police officers were injured, seven banks were vandalized and at least 56 people detained before the clashes between police and masked demonstrators ended.
The protest, occurring on Brazil's national Teacher's Day, helped mark a third week in a row where protests related to striking teachers became violent.
Teachers are currently striking in many states in Brazil, calling for better work conditions and salary increases.
Jose Carlos, an electrician, said that some of the protesters are turning to violence and vandalism to make a point that they want the status quo to change.
"What these boys, these young people want to do, they want to rebel against the condition. They want to change it. They want to study and learn and want to be someone in life, but their own society is standing in their way," Carlos said.
The longest and largest strike thus far has been the teachers' strike in the state of Rio de Janeiro, which began August 8.
The nationwide statistics on how many teachers are currently striking and how many students are affected have been hard to define.
The national Ministry of Education and Confederations of Educational Employees could not give nationwide strike data, saying that the immense number of municipalities involved throughout Brazil made it too difficult to provide information on the number of striking teachers and affected students.