The mayhem that swept River Plate's stadium following the famed soccer club's relegation to the second division is threatening the upcoming Copa America and the future of the team's president.

Police on Monday said 89 people were injured and 55 detained in riots sparked by rampaging fans, humiliated by the club's demotion despite a history that includes 33 league title — more than any other Argentine club.

A prosecutor has ordered the stadium closed until the turnstiles can be inspected. There are suggestions the seating capacity of 40,000 was exceeded by 12,000. The stadium also serves as Argentina's national stadium and is set to hold the Copa America final July 24.