At least eight people were found dead at the headquarters of Corinthians fan group Pavilhao Nove, in Brazil's Sao Paulo, the Military Police has said.
A report from the police said the massacre occurred on Sunday and the eight people were shot inside Pavilhao Nove, reports Xinhua.
Witnesses told the police that at least two armed men arrived in Pavilhao Nove when the fans were preparing for the Sunday's match against Palmeiras.
Police denied the killing was a result of scores being settled between rivals.
Corinthians, based in Sao Paulo, is one of the most famous football clubs in Brazil.