(CNN)Argentine fans were labeled as "sick" by Boca Juniors' president as one of the world's most famous football rivalries descended into chaos, forcing the abandonment of the latest edition of the "Superclasico."
Boca Juniors vs. River Plate: 'Sick' fans force 'Superclasico' abandonment
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Four River Plate players were hospitalized after they were sprayed with an irritant by fans of rivals Boca in the tunnel before coming out for the second half at La Bonbonera stadium in Buenos Aires, according to Reuters news agency.
In the ensuing chaos, the Libertadores Cup last-16 second-leg tie was called off. As many as 1,200 policemen and women had been deployed to keep control of the opposing fans.
"Those fans throwing things to the players at the end, when they were unable to leave the pitch, are not hooligans, these are almost the most expensive seats at the stadium," Argentine sports lawyer Ariel Reck told CNN.
River is yet to confirm to CNN whether the four players have left hospital.
"We will accept the responsibility that we have but, I don't think the players are responsible," Boca president Daniel Angelici told reporters in a news conference.
"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 added, referring to how fans were able to bring the spray into the stadium.
"This is society's problem, not football's problem."
The match was goalless when it was abandoned roughly an hour after the attack. River had led the two-legged tie 1-0 after last week's first match.
Players Leonardo Ponzio and Leonel Vangioni were pictured on television rubbing their eyes, while others were seen pouring water on their faces in an effort to get rid of the irritant.
Ponzio and Vangioni along with Matias Kranevitter and Ramires Funes Mori were the quartet of players hospitalized, with Argentine radio reporting they were being treated for "burns."
"I can't see, I can't see. I am burning. This is not a war!" River defender Funes Mori was quoted as saying by AFP news agency.
"Some of the players of (River coach) Marcelo Gallardo's team suffered the effects of a substance in the tunnel and, after an hour, the match was suspended," said a Boca statement.
Gallardo described the incident as "deplorable" and "shameful."
Prior to the tunnel incident, Boca's supporters had flown a drone over the pitch, which mocked River's relegation to the second tier of Argentine football in 2011.
The governing body of South American football CONMEBOL will decide on Friday whether to replay the match, award it to River or play it at a neutral stadium.
"The violence in Argentine football exist at all levels, from River and Boca down to the smallest match of the lowest division," said Reck.
"We already have a prohibition for away fans to attend games," added the lawyer, who suggested it was time for the authorities to "impose heavy sanctions for violence such as point deduction, relegation, or playing games behind closed doors."
A traditionally working-class side from Buenos Aires' port area, Boca Juniors' most famous player is Diego Maradona. River's nickname is "The Millionaires," with the likes of Alfredo Di Stefano and Hernan Crespo having played for the club -- which is based in the wealthier northern suburbs of the city.
La Bombonera was packed to capacity on Thursday. It's an old-fashioned stadium with fans close to the pitch but kept away from the players by high wire fencing.
The South American equivalent to Europe's Champions League, the Libertadores Cup has had safety issues in the past. In 2013, a Bolivian fan was killed by a flare fired by supporters of Brazilian club Corinthians.