CONMEBOL have given Argentine powers Boca Juniors one day to provide video evidence of their innocence in Thursday's night violent clashes between supporters and players for rivals River Plate in the Copa Libertadores.
Thursday's second leg of the round of 16 turned to chaos at the start of the second half when Boca supporters apparently cut an opening in a tunnel put up to protect players as they entered the field and filled it with pepper spray or mace to douse the opponents.
The players then huddled together at the center of Boca's compact La Bombonera stadium, seeking refuge alongside police and officials who waited more than an hour before suspending the game.
The Copa Libertadores' official Twitter account announced that Boca had already been ejected from the tournament with River advancing to the quarterfinals, but a statement on CONMEBOL's website announced that it would wait until 4 p.m. local time on Saturday to issue a decision.
Se decreta por FINALIZADO: #Boca-#River. @CARPoficial clasificó a cuartos de la #CopaBridgestoneLibertadores. pic.twitter.com/MoT7kRbVum
- Copa Libertadores (@CBrLibertadores) May 15, 2015
If the organisation follows through on the punishment outlined in the Twitter feed, CONMEBOL would rule the game officially ended with the match goalless at the time play was suspended, and River Plate would advance thanks to a 1-0 win in the first leg.
Boca Juniors were the top-seeded team in the knockout stage of South America's elite club competition after winning all six of their matches in the group stage.
The winners of the all-Argentina tie would advance to play Brazilian side Cruzeiro, who defeated Sao Paulo on penalties in the round of 16, though CONMEBOL's schedule for the quarterfinals, released on Friday, did not include this matchup.
River players stumbled onto the field to start the second half of the scoreless match covering their faces, rubbing their eyes and dousing themselves with bottles of water.
The players then huddled together at the center of Boca's compact La Bombonera stadium, seeking refuge alongside police and officials who waited more than an hour before suspending the game.
Trapped at the centre of the field with many of the 50,000 fans refusing to leave, players waited another hour before it was safe to move, and then sought shelter under shields held overhead by police who were battered with flying objects.
"My whole body hurts," River player Leonardo Ponzio said. "They threw -- I'm not sure what it was -- pepper spray at us. This just can't be."
Boca Juniors president Daniel Angelici said he felt "shame and sorrow" over the incidents and said they would accept CONMEBOL's ruling.
"We want to convey from the Boca Juniors team pain, anguish and shame for what happened. There are always misfits who commit acts for no reason, and that has caused such an important match to be abandoned," said Angelici, who insisted that the club complied with all safety protocols, including supplying more than 200 police officers.
"We met all protocols and failed," Angelici added.
River said in a medical statement that at least four players were diagnosed with inflamed corneas after hospital visits, and several were burned from the spray.
The stadium was turned to a crime scene with Buenos Aires public prosecutor Martin Ocampo saying Friday the stadium was being sealed off to "gather evidence."