Football’s world governing body Fifa has opened disciplinary proceedings after crowd trouble delayed Brazil’s World Cup qualifier against Argentina.
The match was halted for 30 minutes after fighting broke out in a stand at the Maracana Stadium in Rio de Janeiro.
Argentina captain Lionel Messi later said there “could have been a tragedy” and criticised police, who had charged at fans with batons.
However, the national federations of both teams now face possible sanctions.
The trouble began during the national anthems before Tuesday’s game.
As police charged fans, some supporters ripped out seats and threw them at officers, while others spilled onto the pitch to escape the trouble.
Players from both sides approached the stand to attempt to calm the situation – Aston Villa goalkeeper Emiliano Martinez was seen trying to grab a baton out of a police officer’s hand.
After players left the field the match was able to begin following a 30-minute delay.
Argentina won the game 1-0.
“Fifa can confirm that its Disciplinary Committee has opened proceedings against the Brazilian Football Association (CBF) and the Argentinian Football Association (AFA),” Fifa confirmed on Friday.
It added Brazil was being investigated for “potential breaches of article 17” of Fifa’s disciplinary code, which deals with order and security at matches.
Argentina is facing disciplinary action over the “crowd disturbance” and the “delayed kick off”.
Sanctions for breaking the rules typically include fines or stadium closures in forthcoming games.