A 36-year-old man was shot dead in the northern province of Tucumán during clashes between rival supporters of the same club before a second-division football match, police have confirmed.
Witnesses said the clash was among supporters of Club Atlético de San Martín in the northwestern city of San Miguel de Tucumán on Monday night.
The fans were heading to the stadium for the top of the table clash against Belgrano, police sources said, quoted by the official Télam news agency.
San Martín president Ruben Moisello said the victim was shot in the neck from behind.
Police cordoned off the area after the incident but the match went ahead regardless, with San Martín winning 1-0.
A murder investigation has been opened and Tucumán Province's deputy police chief Juan Ibañez said the "perpetrator has already been identified."
He added that the crime "happened when people were arriving at the stadium" and took place "outside the security perimeter" deployed as part of a normal police operation.
"If that violence had been replicated inside the club, it would have been catastrophic," local lawmaker Ricardo Bussi told La Gaceta de Tucumán newspaper.
According to the initial reports, the victim and his assailant had had an argument that ended in the shooting as fans of San Martín faced-off against one another.
Also on Monday night, around 15 people were arrested and 13 police officers were injured as angry fans of second division Nueva Chicago tried to break into the changing rooms after their team's 3-2 defeat to Almagro.
According to the Salvemos al Futbol ("Let's Save Football") NGO, violent clashes inside and outside stadiums have resulted in more than 300 deaths since Argentine football became professional in the 1930s, although two-thirds of the deaths have occurred in the past three decades.