Brazilian police say three people were killed in a turf battle between criminal gangs in Rio de Janeiro.

Authorities said Friday that six people were also injured in the shootouts that broke out Thursday evening in the city's Pedreira slum.

Seven buses were burned during the violence, which forced pedestrians to seek cover in a nearby subway station.

The skeleton of a bus that was set on fire during overnight violent confrontations stands at the Costa Barros neighborhood of Rio de Janeiro, Brazil, Friday, Oct. 4, 2019. An armed dispute over territory between criminal factions on Thursday left seven torched buses, with at least three dead and six people wounded, authorities confirmed. (AP PhotoSilvia Izquierdo)

The skeleton of a bus that was set on fire during overnight violent confrontations stands at the Costa Barros neighborhood of Rio de Janeiro, Brazil, Friday, Oct. 4, 2019. An armed dispute over territory between criminal factions on Thursday left seven torched buses, with at least three dead and six people wounded, authorities confirmed. (AP PhotoSilvia Izquierdo)

Wilson Witzel, governor of the state of Rio de Janeiro, says armed gangs use civilians as a "shield" and that authorities will not relent in efforts to fight crime.

Witzel, an ally of President Jair Bolsonaro, has faced criticism for an increase in deaths during police operations. He defends police tactics, saying they must have a freer hand to fight high levels of violent crime.

The skeleton of a bus that was set on fire during overnight violent confrontations stands at the Costa Barros neighborhood of Rio de Janeiro, Brazil, Friday, Oct. 4, 2019. An armed dispute over territory between criminal factions on Thursday left seven torched buses, with at least three dead and six people wounded, authorities confirmed. (AP PhotoSilvia Izquierdo)

The skeleton of a bus that was set on fire during overnight violent confrontations stands at the Costa Barros neighborhood of Rio de Janeiro, Brazil, Friday, Oct. 4, 2019. An armed dispute over territory between criminal factions on Thursday left seven torched buses, with at least three dead and six people wounded, authorities confirmed. (AP PhotoSilvia Izquierdo)

A boy walks past the skeleton of a bus that was set on fire during overnight violent confrontations at the Costa Barros neighborhood of Rio de Janeiro, Brazil, Friday, Oct. 4, 2019. An armed dispute over territory between criminal factions on Thursday left seven torched buses, with at least three dead and six people wounded, authorities confirmed. (AP PhotoSilvia Izquierdo)

A boy walks past the skeleton of a bus that was set on fire during overnight violent confrontations at the Costa Barros neighborhood of Rio de Janeiro, Brazil, Friday, Oct. 4, 2019. An armed dispute over territory between criminal factions on Thursday left seven torched buses, with at least three dead and six people wounded, authorities confirmed. (AP PhotoSilvia Izquierdo)

A family walks past the skeleton of a bus that was set on fire during overnight violent confrontations at the Costa Barros neighborhood of Rio de Janeiro, Brazil, Friday, Oct. 4, 2019. An armed dispute over territory between criminal factions on Thursday left seven torched buses, with at least three dead and six people wounded, authorities confirmed. (AP PhotoSilvia Izquierdo)

A family walks past the skeleton of a bus that was set on fire during overnight violent confrontations at the Costa Barros neighborhood of Rio de Janeiro, Brazil, Friday, Oct. 4, 2019. An armed dispute over territory between criminal factions on Thursday left seven torched buses, with at least three dead and six people wounded, authorities confirmed. (AP PhotoSilvia Izquierdo)