River Plate and Independiente at the centre of shocking child sex abuse scandal

"A medical surgeon knew there had been abuse of children who lived at the boarding facility at River," Andres Bonicalzi, a lawyer for a rape victims charity, said at a press conference.

The complaint was filed with the police in Buenos Aires, and concerns the alleged sexual abuse of players in youth teams between 2004 and 2011, according to judicial sources cited by local media.

"We still don't know the terms of the complaint, but we are making ourselves available to the judiciary and complainants so a full investigation can be carried out," River's secretary general Ignacio Villarroel told 'La Nacion'.

The investigation had up until this point revolved around Independiente, where the testimony of a 17-year-old prompted the team's psychologist to press club directors to contact authorities.

The teenager said he had been encouraged, alongside another 19-year-old player, to prostitute himself to adult men in a trendy Buenos Aires neighbourhood, local press said.

"The structure of this underage prostitution network didn't only operate at Independiente. There are other clubs (involved)," public prosecutor Maria Soledad Garibaldi said last week.

Authorities are also concerned about possible cases of abuse at a third club, Temperley.

At River, one of the three cases brought to attention "concerns a girl from the volleyball teams and the two others from football", Bonicalzi said.

"We are investigating the testimony of provincial families whose children are victims of a paedophile network," she added.

Six people have already been arrested, including referee Martin Bustos, a public relations official and an organiser of youth tournaments.

The victims were coaxed into having sexual relations with adults in exchange for money, promotions to other teams within the club and sporting goods, according to the investigation.

River Plate are the most successful team in Argentine history with 36 national titles, ahead of fellow Buenos Aires outfit Boca Juniors (32), as well as Avellaneda-based duo Racing (17) and Independiente (16).

Independiente have also won the continental Copa Libertadores -- South America's equivalent to the UEFA Champions League -- a record seven times, having never lost a final.

Part of a multi-discipline sports organisation, both River and Independiente have a host of different teams throughout the youth ranks as well as a football academy and an education centre for children throughout their compulsory schooling period.