River Plate's Leonardo Ponzio (R) grabs his head as he walks with a team's aide before going into the field before the second half of their Copa Libertadores soccer match against Boca Juniors in Buenos Aires, May 14, 2015. [Photo/Agencies]

Argentina's Boca Juniors soccer team will play no further role in this season's Copa Libertadores, South America's premier continental club competition, as a result of the attack on River Plate players on Thursday.

Boca has now been barred by the South American Confederation and must also pay a $200,000 fine.

They will play their next four games behind closed doors as punishment for the incident, which saw the players from archrivals River Plate - who will progress to the quarterfinals as a result of the decision - subjected to an attack by a toxic liquid substance.

The game was called off after 45 minutes with the score 0-0. It was played at Boca's stadium in front of 60,000 fans with them trailing 1-0 after the first leg.

River Plate players were returning for the second half when a fan or fans apparently released a chemical irritant into the inflatable tunnel leading from the dressing rooms to the field.