BUENOS AIRES: Confusion continues to reign over the Copa Libertadores scandal in Buenos Aires when River Plate players were attacked with pepper spray at Boca Juniors.

Hooligan fans penetrated the ‘protective’ inflatable tunnel as River’s players emerged for the start of the second half in the last-16 round tie between the old rivals. The match, 0-0 at the time, was subsequently abandoned.

The South American confederation, CONMEBOL, opened a disciplinary investigation. Early reports suggested that Boca – losing 1-0 after the first leg – had been disqualified but other sources suggested they had been given a deadline later today to present a case in their own defence.

The incident added to the sense of an Argentinian game already out of control after the death of a fourth division player two weeks after he crashed into a pitch perimeter wall. This weekend’s league matches have been suspended as a mark of respect.

Television pictures from Buenos Aires on Thursday night and screened across Latin America showed Leonardo Ponzio and Leonel Vangioni rubbing their eyes and other players pouring water over their faces to wash away the irritant. It was an hour before CONMEBOL, the South American Football confederation, confirmed the match had been abandoned.

Ponzio, Vangioni, Matias Kranevitter and Ramires Funes Mori were all treated in hospital later for what local radio reports described as “burns”.

Safety and security concerns meant the players were unable to leave the stadium, all under police guard, until the early hours of the morning.

Marcelo Gallardo, coach of River who won the first leg 1-0, described the attack as  ”deplorable” and “shameful”. Boca president Daniel Angelici said he had apologised to River directors and added: “I can’t believe it. This is all deplorable, it’s a huge embarrassment.”

Boca were among the favourites to win the tournament for the seventh time after winning all six of their group games however their Bombonera [Chocolate Box] box has collected more stadia suspensions – four – than any other in the history of the South American club cup.

The incident is just the latest in a long series of violent events in South American football. In 2013, a Bolivian fan was killed by a flare fired by Corinthians fans during a Libertadores tie.