Brazilian police Thursday said they had made 28 arrests in a crackdown on football violence following a recent outbreak of hooliganism.
The arrests included 20 fans involved in clashes a fortnight ago at a top flight match between Atletico Paranaense and Vasco da Gama which made headlines around the world.
The giant country, which will host next year's World Cup, is no stranger to football hooliganism after a swathe of recent violent incidents.
But the nation was left reeling after four fans were injured on December 8 in the southern city of Joinville.
Atletico Paranaense and Vasco da Gama were fined and told to play several matches behind closed doors as a punishment after shocking scenes which were televised nationwide and beyond.
"Operation Red Card" involved a police sweep in three states -- Rio de Janeiro, Parana and Santa Catarina, police commissioner Dirceu Silveira Junior said.
He said the arrests on charges of inciting violence, criminal association and attempted homicide, should serve as a warning that "violence is inadmissible in football."
Those detained face a maximum of 20 years in jail.
The match at Joinville had been transferred from Atletico's usual home of Curitiba following earlier unrest.
Atletico won the game 5-1 to relegate Vasco but the match was halted for more than an hour as fans fought pitched battles around the stadium.
It emerged the tardy police response was down to Atletico only having contracted private security with military police only on duty outside the stadium.
Brazilian President Dilma Rousseff condemned the violence, as did Sports Minister Aldo Rebelo, and demanded tough action.
Nonetheless, there have been previous political calls for action which have not prevented a series of outbreaks of violence in recent months, not least at World Cup venues including Fortaleza and Sao Paulo.
A similar call went out 15 months ago after violence in Rio and Sao Paulo.
Brazilian media this week put football-related deaths at 30 while sports daily Lance indicated that 234 people have been killed in Brazilian soccer-related violence over the past 25 years.