Buenos Aires, May 18 (IANS): Boca Juniors will appeal against their expulsion from the Copa Libertadores football tournament after their fans attacked River Plate players with an eye irritant spray, the Argentine club has said.

The Buenos Aires outfit were also fined $200,000, ordered to play their next four continental home games behind closed doors and banned from having fans at their next four away matches, reports Xinhua.

Brazilian lawyer Eduardo Carlezzo, who has been hired to defend the club, said Boca would exhaust all avenues to overturn the decision.

"It's not an easy defence," Carlezzo said on Sunday.

"Those images were strong and made their way around the world. Boca knew they could give out a heavy sanction. There was huge pressure to make it, but still we will exhaust all resources available."

The attack occurred during the Copa Libertadores round of 16 second leg between the Argentine rivals at the Bombonera stadium here on Thursday.

The match was called off at halftime with the scores at 0-0. River won the first leg 1-0 and needed only a draw to progress to the quarter-finals of South America's top club competition.

Four River Plate players were taken to hospital for treatment after suffering an inflamed cornea.

The penalty, issued by South American football governing body, means River Plate will now play Cruzeiro for a place in the semi-finals.

Boca had been favorites to win the competition for a seventh time after going undefeated through the group phase.