Brazilian riot police fired tear gas and stun grenades to disperse extremist protesters who ransacked bank branches, shops and car dealerships in central Sao Paulo.
A police spokesman said five people were arrested during the clashes, which followed a peaceful march by 300 demonstrators against Sao Paulo state Governor Geraldo Alckmin.
The protest, called via the internet by the Black Bloc anarchist group, also demanded the demilitarisation of the state police, who have been accused of using excessive force in previous disturbances.
Riot police charged after a small group of extremists, who went on a rampage in the Pinheiros neighbourhood, smashing windows in banks, shops and other businesses.
The police hurled tear gas and stun grenades against the vandals, who retreated to adjacent streets, setting fire to piles of trash.
There was no official word on casualties, but a photographer saw one demonstrator injured by flying glass.
Police, who earlier warned that they would use force to stop “criminal acts,” tightened security to prevent the demonstrators from reaching the city’s main Avenue Paulista, where 50 demonstrators chanted anti-Alckmin slogans.