SAO PAULO (Reuters) - A bystander was killed in Sao Paulo on Sunday (April 3) after being hit in the chest by a bullet fired as Palmeiras and Corinthians fans battled ahead of their Paulista state championship derby game.

Police said at least three people were arrested in that clash and two other mass brawls across the city but they could not say who fired the shot that killed the unidentified man. "One person died in a fight between fans of Corinthians and Palmeiras at around 10:20 this morning," said Sao Paulo police sergeant Andre Aguiar. "We don't know where the shot came from."

Fights between organised fan groups of both sides are common before derbies and Sunday's death was the latest to stem from the battles. Scores of people have died in such fan-related violence over the last two decades.

The game kicked off at 4pm as planned with players from both sides taking the pitch side-by-side in a symbolic show of unity.