A shootout involving fans of Argentine top flight sides Tigre and River Plate injured 13 people, two seriously, local authorities said Monday.
The shooting, which a non-governmental organisation put down to the work of a criminal gang, took place in the northern Buenos Aires suburb of Victoria before Sunday evening's match at River's Monumental.
"This is about money and control of important business. These mafia are tolerated by the clubs, and they are armed," Monica Nizzardo, of the Save Football ONG, told AFP, saying the criminals were involved in mafia-like activities including drug trafficking.
"The clubs' directors bear much of the responsibility. So do the Argentine Football Association, the judiciary and the police," added Nizzardo, who calculates football violence in Argentina has claimed 165 lives since 1979.
In another incident last weekend, a bus carrying players from third tier side Excursionistas was fired on as it returned to the capital. Nobody was hurt.