Policemen fire rubber bullets and tear gas against teachers during a protest in Curitiba in Parana state April 29, 2015. [Photo/Agencies]

RIO DE JANEIRO -- Over 150 people were injured on Wednesday in a confrontation between protesting teachers and the police in southern Brazil.

The bloodshed in Curitiba, Parana state, marked the second consecutive day of clashes since teachers in the state started camping outside of the State Assembly since Monday.

The protest was against a bill that makes changes in Parana Previdencia, the state civil workers' pension and retirement system.

While the State Assembly voted the bill, police and protesters fought outside. The protesting teachers used sticks and stones to fight the cops, who used stun bombs, rubber bullets, dogs, pepper spray and tear gas against the teachers. In addition, the police threw stun bombs from a helicopter.