Two football supporters have been shot dead by rival fans in Brazil, according to media in the South American country.
The incident happened in Brazil's north east, near the Arena Castelao World Cup stadium in Fortaleza.
suggest two men who supported Ceara were shot in the head by two Fortaleza fans in a vehicle.
It is the latest in a series of issues that have led to questions about the nation's ability to stage the 2014 World Cup and 2016 Olympic Games.
As well as delays to the rebuilding of the Maracana Stadium, Rio 2016 venue, the Joao Havelange Stadium, has been
Analysis - Tim Vickery, BBC Sport
"Brazil have every reason to be concerned with domestic problems. Brazil is leading the ranking for the number of football-related deaths. In terms of the World Cup and Confederations Cup, it is not much of a concern as these local rivalries are not involved - it is a different type of support. But it is not good publicity for the country.
"Brazil is a very violent society. Football is like strong beer, some people cannot take it. This leads to more and more fatalities."
Folha de Sao Paulo newspaper
claim Ceara fans, who had seen their side win 1-0, had earlier started a fight by throwing stones at Fortaleza supporters in an attack which happened around three miles from the stadium.
The Arena Castelao has been undergoing security tests ahead of its hosting of the Confederations Cup in June, prior to next year's World Cup.
However, World Cup local organising committee official Tiago Paes is adamant that there are no security fears concerning the stadium and the area.
"There is a lot of training work by the military police, civil police and even the army," he said.