A 14-year-old Bolivian boy was killed by a flare allegedly thrown by Corinthians fans during a Copa Libertadores match on Wednesday.
The incident took place during Corinthians 1-1 draw with San Jose at the Bolivian side's Jesus Bermudez stadium in Oruro, Brazilian and Bolivian media reported on Thursday.
The boy was hit in the eye and died almost instantly, according to the doctor who attended to him in hospital. Bolivian media identified the child as Kevin Beltran, a San Jose fan.
"There was a loss of brain matter as the projectile, a plastic tube, penetrated the (boy's) skull. Due to this, death was immediate," doctor Jose Maria Vargas told local media at the Hospital Obrero in Oruro, according to Brazil's Globo.
The boy was struck by the flare minutes after Corinthians took an early lead through Paolo Guerrero. Witnesses told local media the flare came from a section of the ground occupied by the away fans.
Many San Jose supporters reportedly left the stadium in tears on hearing about the incident, while Corinthians coach Tite was shocked by what had happened.
"I would exchange my world title for the boy's life," he said. "I'm sorry about what happened tonight. We can't talk about football, it's my feeling and that of the players, we couldn't utter a word in the dressing room.
"Corinthians is available to try to help in whatever way with what happened. I didn't want to be here (at the press conference), what happened is too heavy to be able to talk of football, I'm sorry."
A dozen Corinthians supporters identified by local police were arrested and a spokesman for San Jose said a criminal investigation would be opened, match broadcasters Fox Sports reported.
According to Brazilian media, Corinthians could be kicked out of the competition if it is confirmed that some of their fans were responsible for the boy's death.