Sky News 
Friday, Oct 17, 2008
Striking police detectives in Sao Paulo have been involved in violent clashes with state troopers during a protest march over police pay.
Brazilian television news showed a melee as hundreds of state police in riot gear tackled plainclothes police investigators.
It came after the protesters tried to break through a barrier protecting the state government palace.
Officers fired shots, tear gas and shock bombs.
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The Albert Einstein Hospital, located a few blocks from the government palace, said in a statement that it had treated 13 people who were injured in the clashes, none seriously.
- A d v e r t i s e m e n t
It did not say whether those injured were state police officers or detectives.
Brazilian states have two separate law enforcement groups – a uniformed police force in charge of maintaining public order, and the so-called civil police who are plainclothes investigators.
In some cities there are also municipal guards in charge of protecting public property.
Detectives in Sao Paulo state have been striking for a month to demand better pay.