FIFA are investigating allegations that Spain/Portugal and Qatar colluded over vote-trading in their World Cup bid campaigns.
The two bids are being investigated by FIFA's ethics committee, according to widespread reports which cite high-level sources at FIFA.
Collusion between bidding countries is explicitly forbidden by the regulations but FIFA chiefs have ruled out postponing the December 2 vote for the 2018 and 2022 World Cup hosts.
Spain/Portugal are one of four bidders for the 2018 tournament against England, Russia and Holland/Belgium. Qatar, Australia, the United States, Japan and South Korea are contesting the 2022 vote.
The investigation will run alongside the ethics committee's probe into two senior FIFA officials who have been provisionally suspended after being caught up in a World Cup cash-for-votes scandal.
Amos Adamu from Nigeria and Tahiti's Reynald Temarii, two of the members of FIFA's 24-man executive committee which will decide on the 2018 and 2022 World Cups, were trapped by a Sunday Times undercover investigation asking for cash in return for their votes.
The pair appeared before the FIFA ethics committee yesterday and were suspended "from all football activity'' pending a final hearing next month. Four other FIFA officials - Slim Aloulou, Amadou Diakite, Ahongalu Fusimalohi and Ismael Bhamjee - have also been provisionally suspended from taking part in any football-related activity.
FIFA president Sepp Blatter insisted that his organisation was not corrupt. He told a news conference in Zurich: "I was a little bit surprised that you say 'is FIFA corrupt?' FIFA is actually in the world of sport a well-recognised organisation and institution and if there are some activities that are against the ethics and the morals (of FIFA) that's why the ethics committee came in.
"Our society is full of devils and these devils, you find them in football. We have to fight for fair play, we have to fight for respect and especially we have to fight that the people in charge of FIFA behave as they should do and if this is not the case then we have to intervene.
"As the president of FIFA I appeal to and I expect all members, not only of the FIFA executive committee but all members of the FIFA family, to behave in an honest, sincere and respectful manner because football is based on discipline, respect, fair play and solidarity. We have the necessary tools to intervene when needed and that is what we have done.''
The Sunday Times has provided all their evidence to FIFA - 90 minutes of footage and a full transcript - and further revelations are expected at the weekend. The ethics committee will reconvene in the middle of November but it is not clear if Adamu and Temarii will be replaced on the executive committee before the December vote if they lose their places permanently.