Police in Brazil's biggest city are investigating the shooting deaths of at least 17 people within the space of about three hours.

Officers are investigating if shootings on the western outskirts of Sao Paulo are related.

At least 10 of the dead were shot at a bar after hooded men got out of a car and opened fire.

Not far away, one young man was shot outside an ice cream store, while another was shot by two men riding a motorcycle.

Other shootings took place in five other areas.

Witnesses told the Folha de S.Paulo newspaper that in at least two instances the gunmen arrived and asked who had criminal histories. Those who said they had were shot.

The shootings happened in the neighbouring suburbs of Osasco and Barueri.

The mayor of Osasco, Jorge Lapas, told the Globo TV network the killings might have been in reprisal for the recent shooting deaths of two police officers.