FIFA president Sepp Blatter has confirmed he has been informed of allegations that Cameroon players were involved in match-fixing at the World Cup.
The allegations strike at the heart of the World Cup's integrity and Blatter said he was waiting for the outcome of an investigation.
The Cameroon football federation (FECAFOOT) has announced its ethics committee will probe allegations of fraud in three Group A matches, particularly the 4-0 defeat to Croatia on June 18 in Manaus.
FIFA's security department is also believed to be looking into the claims.
Blatter told Press Association Sport in Rio de Janeiro: "Yes I have been told about this but let them do their work on this investigation."
Cameroon headed home from the World Cup after losing against Brazil and Mexico, as well as Croatia, to finish bottom of Group A.
German magazine Der Spiegel revealed that convicted match-fixer Wilson Raj Perumal correctly predicted the result - a 4-0 defeat against Croatia and that a player would be sent off in the first half - in a Facebook discussion with a journalist before the game.
Not only was the scoreline correct, but Cameroon's Barcelona midfielder Alex Song was sent off before half-time for elbowing Croatia's Mario Mandzukic.
The game was also marred by an incident deep into the second half as Benoit Assou-Ekotto looked like he tried to head-butt team-mate Benjamin Moukandjo.
FIFA's head of media Delia Fischer would not confirm or deny whether its security department - which is made up of former police officers - has also launched an investigation, but it would be unthinkable for it not to have done so and left it for the Cameroon federation to investigate its own players.
The FECAFOOT statement read: "Recent allegations of fraud around Cameroon 2014 FIFA World Cup three preliminary games, especially Cameroon vs. Croatia, as well of the 'existence of seven bad apples [in our national team]' do not reflect the values and principles promoted by our administration, in line with FIFA code of conduct and the ethics of our nation.
"We wish to inform the general public that, though not yet contacted by FIFA in regards to this affair, our administration has already instructed its ethics committee, to further investigate these accusations.
"We are strongly committed to employ all means necessary to resolve this disruptive matter in the shortest delays.
"In the meantime we legitimately request that any related information, unless brought before our federation and/or its ethics committee, be held for or treated as mere assumption.
"We wish to reinstate that in 55 years of existence, FECAFOOT has never been sanctioned for, involved in, or even linked to match fixing or any fraud of any kind."
In his conversation with Der Spiegel, Perumal wrote: "In this team there are seven bad apples."
Perumal, originally from Singapore, told the magazine he believes Cameroon manipulated all three group games.
Last week, FIFA's security director Ralf Mutschke said there had been no suspicious betting patterns with any match and added: "So far we have no evidence of a rigged game."
Chris Eaton, FIFA's former security chief who is now director of Qatar-based International Centre for Sport Security (ICSS) said if proved that Perumal's prediction was made before the match it would have to be treated "extremely seriously".
Eaton said: "The ICSS is aware of the allegation first reported by Der Spiegel that Wilson Raj Perumal, a well-known and convicted match fixer, apparently accurately predicted the outcome of a specific match result and foul outcome for a game at the FIFA World Cup, using a Facebook account.
"If it is confirmed that the advice from Perumal was made before the match and is accurate to the overall result and red card, then this allegation will no doubt be treated extremely seriously by football, governments and beyond."
Eaton added however that Perumal had made other predictions which had not materialised and that the regulated sport betting industry had not reported suspicious betting on the match.
He said: "I understand that he has made other 'predictions' during this competition that have not proved accurate."