A 17-year-old fan of Russia's Rubin Kazan football club died of unknown causes in the stands during the team's home game on Saturday, state news agency TASS reported.
"Our fan felt unwell in the stands. Ambulance workers were nearby, but to our deepest regret his life could not be saved," Rubin Kazan's general director Airat Garayev was quoted as saying.
The deceased was identified as Ilkham Kharisov, who had traveled from the nearby city of Zelenodolsk to attend the match against FC Ural. Garayev said the cause of death had not yet been determined.
The club's players have pledged to collect funds for Kharisov's parents, the report said. Rubin Kazan coach Rinat Bilyaletdinov has suggested that players and fans take part in a one-day tournament to be named in honor of the deceased fan.
Kazan is among the dozen Russian cities that will host World Cup matches in 2018.