Brazilian authorities say a 16-year-old fan was shot dead in a confrontation involving rival fan groups and police after a soccer match in southern Brazil.

The fighting happened after Novo Hamburgo and local rival Aimore drew 2-2 in the first division of the Rio Grande do Sul state championship on Sunday.

It wasn't immediately clear if the shot that killed the Novo Hamburgo fan was fired by Aimore supporters or by police officers trying to break up the disturbances outside the stadium.

The fan reportedly belonged to one of the fan groups.

Authorities said they were investigating.

The death came a day after dozens of fans of Flamengo, Brazil's most popular club, invaded the changing room of an opposing team and injured the rival goalkeeper.