Gunmen have killed seven people and wounded 10 during loud street celebrations after the Palmeiras football team won the Brazilian Cup.
Police say the shooting took place in the city of Osasco.
None of the victims were Palmeiras fans.
The gunmen "took advantage of the noise of fireworks to mask the noise of the gunshots," police say.
In Brazil, fireworks are often set off during celebrations commemorating a football club's victory of a major tournament.
Police say they the killings could be drug related.