Brazilian police detained more than 100 football fans ahead of a high-profile match in the Rio de Janeiro state championship on Sunday.
Authorities said supporters of Fluminense and Vasco da Gama were taken into custody after fighting outside the Engenhao stadium.
"The first trouble was something we're used to seeing, fights between fans of Vasco and fans of Fluminense," police commander Lt. Col. Joao Guimaraes told Globo News TV, as reported by Reuters.
"The second fight was a new phenomenon in Brazilian football, fights between fans of the same team."
Guimaraes added, using the name given to Vasco fans: "None of them are worried about football and none of them are worried about being Vascainos. They don't care about their club."
Rio police intervened with stun grenades and rubber bullets as the rival fan groups from both clubs confronted each other with rocks and metal bars -- no serious injuries were reported.
Brazil has endured a wave of fan violence less than a month into the new season, with several incidents reported across the country. In the most serious case, a 16-year-old boy died after a confrontation between fan groups.
Vasco da Gama won the match, which was attended by 7,338 people, 1-0 courtesy of a late penalty from Luan.