
Brazilian media said the demonstration was organized online, using social networks like Facebook and Twitter and several blogs that have emerged in Brazil to protest Assange’s arrest.
Assange, who was detained after presenting himself to a police station in London Tuesday, is being held in extradition custody over allegations of sexual assault in Sweden.
The British consulate in Sao Paulo is closed Saturdays. Police watched the rally from a distance, although no violent incidents were reported.