Nineteen people were killed and seven injured overnight in a wave of shootings in Brazil's biggest city Sao Paulo, a security official said Friday after reports of a massacre in the suburbs.
Those numbers are still considered preliminary, Alexandre de Moraes, head of the Sao Paulo state security body, told reporters.
Earlier, a spokesman for the security forces had described the wave of killings late Thursday as "unusual."
Media reports said the shootings occurred in 10 places in the Osasco area, with two more attacks in Barueri, all in a period of about two and a half hours.
Globo News television broadcast security camera footage showing a group of masked assailants entering a bar, ordering clients to raise their hands in the air, then shooting them.
The mayor of Osasco, Jorge Lapas, said video footage supports a theory that the killings could have been reprisals for the earlier death of a police officer.
"We want to take measures so that the situation does not worsen over the coming days," he said.