Four Botafogo fans were wounded by gunshots after the team’s match against Flamengo in Rio de Janeiro during a weekend marked by violence between rival football supporters and police across Brazil.

Authorities in Rio said the four fans were hospitalised after being shot early Monday but their injuries were not life-threatening.

They were shot at a plaza by unknown assailants who drove by just after a fight between supporters from both clubs.

Dozens of other football supporters were also injured or detained at other venues on Sunday in clashes between rival fans and fights between hooligans and police.

In the interior city of Campinas, police had to use rubber bullets to disperse the crowd before the match between Ponte Preta and Sao Paulo.

Supporters from both clubs clashed outside the Moises Lucarelli stadium and riot police had to be called up to intervene.

Television images showed Ponte Preta fans throwing rocks at the officers and at journalists, damaging several vehicles.

No major injuries were reported but several arrests were made, according to local media.

A few media outlets were not able to cover the match because of the lack of security.

Also on Sunday, Palmeiras fans were attacked by a group of Corinthians supporters as they left for the team’s match against Santos in Presidente Prudente.

The Corinthians fans reportedly threw rocks at the buses carrying Palmeiras supporters as it passed near Corinthians’ headquarters in Sao Paulo.

Nobody was seriously injured but police made nearly 20 arrests.

In the southern city of Porto Alegre, fan groups from club Internacional fought each other near the Estadio Olimpico before the team’s match against rival Gremio. No significant injuries were reported.

Fan violence in Brazil is not uncommon and high-profile matches between rival clubs are always a concern to police.

Four Goias fans were wounded by gunshots earlier this year in Goiania and another four were shot after a fight that left 80 people detained in Rio last year. All recovered from their injuries.

The last reported death from fan violence in Brazil happened in November 2010, when a 19-year-old Cruzeiro fan was repeatedly beaten with iron bars during a brawl between dozens of rival fans in Belo Horizonte.

Earlier that year, then President Luiz Inacio Lula da Silva approved harsher punishments for fan fighting, including fines and prison terms of up to two years for anyone involved in acts of violence inside the stadium or within a radius of up to 5 kilometers from the venue.

A study at the time showed that more than 40 people were killed in connection to Brazilian football matches between 1999 and 2009.