Rowdy Brazilian youths are increasingly resorting to violent flash mobs in shopping malls, a phenomenon that is causing concern among authorities and shopkeepers.
Known as "rolezinhos", the sudden rampages are coordinated via social media, bringing together hundreds of thrill-seeking youths, mainly from underprivileged areas, who sometimes trash stores and cause disturbances.
On Saturday, one thousand teenagers massed in a shopping mall in eastern Sao Paulo and fought security guards and police attempting to deny them access.
Police used tear gas, rubber bullets and batons to disperse the youths, according to videos taped by the participants and posted on social media networks.
Three youths were detained.
Sao Paulo state Governor Geraldo Alckm promised an investigation into allegations of police brutality.
Sao Paulo Mayor Fernando Haddad, for his part, said his administration would expand and improve recreational facilities for underprivileged youths in need of healthier outlets.
But shopping centers and store owners have taken a tougher line, with some pointing out that malls are private not public spaces.
Last weekend, Sao Paulo's posh JK Iguatemi mall warned that anyone taking part in a flash mob there faces fines of up to $4,500 under a court order.
"We support this measure, obviously, we side with the shopkeepers and the employees of these shopping malls," said Fernanda Pedrini, a spokeswoman for the Brazilian Association of shopkeepers (Alshop).
"These disturbances often end in robberies," she told AFP.
Others, however, have protested over discrimination and racial profiling in enforcing bans on the gatherings.
"You cannot make a selection based on illegal criteria such as the appearance of people," Virgilio da Silva, a constitutional law professor at the University of Sao Paulo, told the daily O Estado de Sao Paulo.
More "rolezinhos" are being planned via Facebook, including one calling thousands of youths to go to Shopping Leblon, in Rio's posh southern zone, on Sunday.
The phenonemon is also spreading to other
cities in Sao Paulo state as well as in Brasilia, the federal capital.
Saturday, non-government organizations and social movements have scheduled a protest in Sao Paulo's JK Iguatemi mall to denounce discrimination contra "young blacks, the poor and fans of funk music."