An attack on Boca Juniors' team bus resulted in the Copa Libertadores final second leg being suspended, leading Conmebol to appeal for calm.
Conmebol president Alejandro Domínguez rued a "sad day for South American football" and condemned those responsible for the violence which forced the suspension of the Copa Libertadores final second leg between River Plate and Boca Juniors.
Boca travelled across Buenos Aires on Saturday with the final tied at 2-2 after the opening game at La Bombonera, but their bus was showered with projectiles on the way to River's El Monumental stadium, with some smashing windows of the vehicle.
Eventually the bus arrived at the ground, but reports suggested three players had to be taken to hospital for assessment, while some were believed to have been affected by the use of pepper spray.
Conmebol medical officials had deemed the injuries sustained to be "superficial" and approved the match to proceed despite Carlos Tévez's protests that Boca were unfit to play.
After discussions which led to several delays, the game was eventually suspended for 24 hours until 17:00 local time (20:00 GMT) on Sunday, and Dominguez called for those responsible to feel the full force of the law as a consequence.
Un día triste para el fútbol sudamericano. CONMEBOL se solidariza con los jugadores, sus familias y todos los afectados.— Alejandro Domínguez (@agdws) November 25, 2018
Lo que debió ser un encuentro deportivo para vivir, disfrutar y compartir lo mejor del fútbol sudamericano se convirtió en una vergüenza.
"A sad day for South American football," Domínguez began in a series of tweets posted on his official Twitter account.
"CONMEBOL sympathises with the players, their families and all those affected. What should have been a sporting event to live, enjoy and share the best of South American football became a shame.
"CONMEBOL condemns the violent and criminal acts that put lives at risk, attacked the livelihood of professional athletes, affected millions of good fans and embarrassed their club, their football, their country and their continent.
"CONMEBOL demands from the competent authorities' immediate action and offers all its collaboration to identify, capture and prosecute those responsible.
"These acts cannot go unpunished. Those responsible must be burdened with the full weight of the law and the rejection of society.
"CONMEBOL calls on the responsible bodies to reinforce the protocols and redouble efforts to guarantee public order and the safety of the players, technical bodies and fans at the end of this Sunday.
"CONMEBOL calls for Sunday to see a final in peace, with respect for the rival and showing the best face of South America to the world. We invite all fans who share the values of fair play to express themselves with the hashtag #SudamericaQuiereFutbolEnPaz [South America wants football in peace].
"I call on all everyone in South American football to set a priority and join efforts to identify, understand and combat the causes and acts of violence that permeate our football every year."