Four River Plate players were taken to hospital on Thursday after they were reportedly attacked with tear gas by Boca Juniors fans.
The Copa Libertadores last-16 tie was abandoned at half time with the match goalless after the alleged attack took place in the tunnel just before the second half.
According to Reuters, rival fans sprayed tear gas into the eyes of Leonardo Ponzio and Leonel Vangioni, while teammates Matias Kranevitter and Ramiro Funes Mori were also affected as they too were taken to hospital.
An Argentinian radio described the players' injuries as "burns" after they were given medical treatment.
