Fifa has refused to comment on allegations that Cameroon players were involved in match-fixing in their World Cup games.
Sepp Blatter, the Fifa president, said he was aware of the issue, telling reporters in Rio: "Yes I have been told about this but let them do their work on this investigation."
Fifa spokeswoman Delia Fischer refused to comment on whether the governing body was investigating the claims.
"As we have said consistently - prior to the Fifa World Cup and now during it - we do not provide any comments as to whether or not an investigation is underway with regard to any alleged manipulation in any match, amongst others so as not to compromise any possible investigations," she said.
Cameroon lost all three Group A matches, including a 4-0 defeat by Croatia.
Disgraced former New Zealand cricketer Lou Vincent has admitted match-fixing and says he is prepared to accept any punishment he receives.
The 35-year-old was charged by the ECB last month after allegations of his involvement in the spot-fixing of dozens of matches.
"My name is Lou Vincent and I am a cheat," the former top-order batsman said in a statement today.
"I have abused my position as a professional sportsman on a number of occasions by choosing to accept money through fixing.
"I have lived with this dark secret for many years. I have shamed my country. I have shamed my sport. I lost faith in myself and the game. I abused the game I love. "Laying bare the things I have done wrong is the only way I can find to begin to put things right."
Vincent is expected to receive a life ban from the sport.
Cameroon's football authorities have confirmed they are looking into claims of "fraud" surrounding the national team's games at the World Cup.
"Recent allegations of fraud around Cameroon's three 2014 World Cup games, especially Cameroon v Croatia, as well the existence of "seven bad apples (in our national team)" do not reflect the values and principles promoted by our administration," FECAFOOT said in a statement.
“We are strongly committed to employ all means necessary to resolve this disruptive matter with the shortest delay,” FECAFOOT's interim president Joseph Owona said.
The allegations stem from reports in German magazine Der Spiegel that a convicted fraudster had accurately predicted Croatia would win 4-0 and that a player would be sent off.
Cameroon's Football Association says it will investigate claims of match-fixing in some of the national team's World Cup games.
Far Eastern businessmen Chann Sankaran and Krishna Ganeshan have been found guilty at Birmingham Crown Court of involvement in a football match-fixing plot.
Jurors cleared footballer Hakeem Adelakun of the same charge.
Nigeria manager Stephen Keshi told reporters: "We are not part of this, we do not have interests in this. We are here to play football and that's it.
"If they want to investigate it whenever they want, that's their problem. We don't know anything about this stuff."
Detectives have launched an investigation into alleged attempts to fix a football friendly between Scotland and Nigeria in London tomorrow night, it has been reported.
A Scottish FA spokesman: "We are liaising with the relevant authorities and will prepare for the match as normal."
Officers from the National Crime Agency were said to be liaising with the Scottish Football Association after the match, to be played at Fulham's Craven Cottage ground, was 'red flagged', the Daily Telegraph reported.
Two men charged in connection with alleged match-fixing in English football are to appear in court today.
Chann Sankaran, a 33-year-old Singapore national, and Krishna Sanjey Ganeshan, a 43-year-old with dual UK and Singapore nationality, have been charged with conspiracy to defraud.
The men were among seven people held as part of the National Crime Agency's investigation, with the five other men on bail pending further inquiries.
A European police investigation says that World Cup and European Championship qualification matches are among those that have been fixed.
European police authorities today said that a Champions League game played in England is among 380 matches subject to suspected match-fixing.
Europol are revealing details of their investigation into European match-fixing at a press conference in The Netherlands.
Investigators have not revealed the identity of the English Champions League game that they believe to be corrupt.