The match was scheduled to be played Saturday but was postponed until Sunday after chaos ensued in Buenos Aires.
Boca’s bus was attacked with windows broken and tear gas in the vehicle, injuring and affecting a number of players.
The decision to postpone the game came despite the stadium being full with carnage still going on outside River’s El Monumental stadium.
It was decided to play the game at 5pm local time on Sunday (8pm).
But reports now suggest that is in doubt with authorities suggesting they will not tolerate the bad behaviour.
Local newspaper Popular said: “Urgent, El Monumental is closed. The police of the city have refused to provide security for tomorrow.”
Meanwhile Ole report the game cannot be played on Sunday as things stands.
It’s believed that River Plate will work to try to overturn the decision and all fans into the stadium.
Away supporters had already been banned under an existing ruling.
Boca star Carlos Tevez believes the match should not go ahead, though has his doubts over whether all is fair.
According to journalist Peter Coates, Tevez has said that he believes CONMEBOL want River to win.
Coates tweeted: “Meanwhile Carlos Tevez is talking to the press again & not mincing his words.
“He said the game shouldn’t go ahead tomorrow & suggested that CONMEBOL want to give the trophy to River.”
Clarin said six players had vomited in the dressing-room after gas drifted into bus windows smashed by River fans outside the stadium.
The incident occurred three years after a Copa Libertadores last-16 tie between the same teams was abandoned at halftime after Boca fans attacked the River players with pepper spray in the tunnel.
River were given a bye into the quarter-finals and Boca were kicked out the competition.