The build-up to the Copa Libertadores final between Boca Juniors and Fluminense became a violent affair on Thursday after Boca fans suffered police repression following a clash with Flu supporters. Argentine fans in Rio de Janeiro to see the game claim the Brazilian police let the locals attack them and then intervened, hitting Boca supporters with tear gas and arresting several of them.

The incident began when a faction of the “Young Flu” torcida, one of Fluminense’s many organized fan groups, invaded the Copacabana beaches where Boca fans were resting and partying. The Argentine fans were near the Fan Zone, an area installed by South American football’s governing body Conmebol where fans from both teams can enjoy music and other entertainment.

“We were partying on our own when Fluminense fans came to throw chairs and sticks, hit us and rob us,” a Boca fan told public news agency Télam. He said that passports, money, and other belongings were stolen.

According to eyewitnesses, the Fluminense fans found the area had been cleared for the attack by Rio de Janeiro police, who did not intervene to help Boca fans. “We were on the beach when people from Fluminense appeared. All of a sudden, the police came and repressed us,” another Boca Juniors fan told Télam. 

The Rio de Janeiro military police cracked down on dozens of Boca fans with pepper spray and tear gas. Two Argentine fans and a Fluminense supporter were arrested close to the Othon Hotel, where Boca fans are based. It is estimated that there are more than 60,000 Argentine fans in Rio de Janeiro, just a third of whom hold tickets for Saturday’s game at the Maracanã Stadium.

Argentine ambassador to Brazil Daniel Scioli condemned the incident. “The police’s actions were brutally repressive,” Scioli told Télam. “These fans didn’t steal anything, they didn’t attack anyone, they were on the beach wearing their jerseys with pride and the Fluminense fans came to attack them first.”

Carlos Eduardo Mansur, one of Brazil’s most famous football commentators, also called out fans and the police for the violent episode. “It was an act of cowardice against the Boca Juniors fans,” he said during the program Troca de Passes. “It’s very sad, it was cowardice and violence against families. Rio lost an opportunity to show the world how well it receives tourists.”

Conmebol issued a statement after the events, calling on “Boca and Fluminense fans to share together the moments of joy and celebration that football offers.” The organization rejected the acts of violence, claiming football’s values are peace and harmony. Conmebol leaders will meet this Friday with security agencies in Rio de Janeiro to reinforce security ahead of the Copa Libertadores final.

Boca fans have called for a gathering with flags on the Copacabana beach this Friday to continue celebrating. Supporter groups of Flamengo and Vasco da Gama, Fluminense’s traditional rivals, have come out in support of Boca fans.