FOUR River Plate players were taken to hospital after appearing to be attacked with tear gas by Boca Juniors fans in 'deplorable' scenes.

The Copa Libertadores clash between the fierce Argentinean rivals had to be postponed at the Bombonera as players were escorted from the park by police with riot shields.

River were 1-0 up from the first leg of the last 16 encounter but trouble erupted when the players made their way out of the tunnel for the second half last night.

Television footage appeared to show Leonardo Ponzio and Leonel Vangioni rubbing their eyes, while other players poured water on their faces, and they were later taken to hospital for treatment on 'burns' alongside team-mates Matías Kranevitter and Ramiro Funes Mori.

Boca president Daniel Angelici apologised for the incident but insisted the team should not be punished for the actions of fans after chaotic scenes in South America.

"We will accept the responsibility that we have but I don't think the players are responsible," Angelici said. "We will do all we can to help the police and we hope to find those responsible as soon as possible."

Angelici denied the barras bravas, or hooligan firms, were behind the attacks and insists it is impossible to stop supporters concealing smuggling banned items in the ground.

"An aerosol is small, I don't know how it works, but it is very powerful, it can fit in your pocket and when there are almost 50,000 people it can get by security," he said. "This is society's problem, not football's problem. These people are sick."

Conmebol officials are expected to decide today whether the match is to be replayed, completed at a neutral venue or whether the tie is awarded to River Plate.