BUENOS AIRES, Argentina -- Police were investigating Friday after a high-profile match between Argentine clubs Boca Juniors and River Plate was stopped when visiting players were sprayed by fans with an eye irritant believed to be pepper spray or mace.
Buenos Aires public prosecutor Martin Ocampo said Boca's stadium has been closed so investigators can "gather evidence."
The Copa Libertadores match between the Argentine rivals was played before about 50,000 fans. River won the first leg 1-0 last week, and Thursday's match was 0-0 when it was suspended before the second half could begin.
The suspension and fan attack on rival players is the latest in the endemic violence that threatens almost every football match in Argentina.
The match turned to chaos when River players, entering the field for the second half, came out of a temporary tunnel rubbing their eyes and pulling their shirts over their faces. Many poured water over their faces to clear their eyes. Police and officials waited on the field for more than an hour before suspending the game.
"I can't say that they [Boca] lost control with the scant information I have," Ocampo said.
But Sergio Berni, at top Argentine national security official, put the blame squarely with Boca.
"Boca is the only one responsible, this is undeniable," Berni told reporters. "The club neglected to provide internal security."
River and Boca players milled around at the center of the field after the match was called off, apparently fearing for their safety because many fans were trying to wait out attempts to clear the stadium.
River said in a medical statement that at least four players were diagnosed with inflamed corneas, and several were burned from the spray.
"My whole body hurts," River player Leonardo Ponzio said. "They threw -- I'm not sure what it was -- pepper spray at us. This just can't be."
Television images showed a fan sliding a hand through the make-shift tunnel that shields players entering the field.
River Plate officials say they are advocating that the disciplinary courts put Conmebol's Rule 23 into place, which would sanction Boca Juniors by taking a point away and not allowing the rest of the game to be played out to an empty stadium.
Argentina already bans visiting fans from attending matches, but that has not stemmed the violence as rival hooligans gangs affiliated with the same club often battle over turf, rights to park cars and resell tickets.
Nestor Benitez, a spokesman for the governing body of South American football, said officials were awaiting a report from the referee and were likely to say Saturday how the suspended game would be handled.
This was the third match in 12 days for the two Buenos Aires rivals. Boca defeated River 2-0 to take the lead in the Argentine first division, just ahead of River. Four days later, River defeated Boca 1-0 in the first leg of the round of 16 at River's Monumental stadium.