Riot police clashed with striking ordinary police officers in Sao Paulo as they blocked the latter from forcing their way into the state government building, live television pictures showed.

Black-clad military police were seen on Thursday massed behind riot shields, occasionally firing teargas canisters and flashbombs to keep uniformed and plainclothes civilian state police from entering the building. Other military police arrived on horseback.

At least 22 people were injured in the clash, including a military police colonel with a gunshot wound to the leg, according to media reports.

Civilian police officers in the state of Sao Paulo have been on strike for a month to demand the governor, Jose Serra, meet them to negotiate a 15 percent pay rise.

AFP