Brazilian protesters clashed with police on Rio de Janeiro's beachfront ahead of a controversial multi-billion dollar oil rights auction that was held in a nearby luxury beachfront hotel.
In the last of a series of violent demonstrations fuelled by black-clad "Black Bloc" anarchists to hit Brazil in recent months, stone-hurling protesters overturned the car of one local TV channel and set it ablaze before being dispersed by police that fired rubber bullets and tear gas.
About 300 demonstrators had gathered to protest against the involvement of foreign companies in Brazil's oil production.
They were met by some 1,100 security personnel who had been deployed to protect premises of Hotel Windsor, in the upmarket district of Barra de Tijuca, where government official and oil companies' representative were taking part in the auction for Libra, an offshore field that could hold up to 12 billion barrels of oil.
Sunbathers and tourists watched the chaotic scenes, in which several protesters were injured. Demonstrators later moved in central Rio to demonstrate in fort of the headquarters of state-run oil giant Petrobras.
Rights to right to develop the site were won by the sole bidder: a consortium led by Petrobras and backed Shell, Total, two Chinese firms.
Under a recently approved legal framework Petrobras has been designated as the sole operator of new found oil deposits has to hold a minimum 30% stake in oil blocks.
The company added a 10% stake on top of what it was already entitled. The remaining shares were divided between Shell and Total, each accounting for 20% and Chinese firms CNOOC and CNPC with 10% each.
The auction was described as a success by of the government's National Petroleum Agency.
"It is hard to imagine a more successful outcome. These companies are among the world's 10 most valuable in the energy branch," the agency president, Magda Chambriard told the BBC.