Russia and Qatar could lose the 2018 and 2022 World Cups respectively if evidence emerges of bribery, leading FIFA official Domenico Scala has said.
The countries deny wrongdoing in their bidding processes and Scala admits he has not seen evidence of corruption.
Scala is the head of FIFA’s audit and compliance committee.
But he said: “Should there be evidence that the awards to Qatar and Russia came only because of bought votes, then the awards could be cancelled.”
Speaking to Swiss newspaper Sonntagszeitung, he added: “Until today, the respective evidence has not been provided.”
Scala made similar comments at the end of 2013, but in light of events at FIFA in the past two weeks this will be viewed as a more serious warning.
Seven senior FIFA officials were arrested in a high-profile dawn raid at a Zurich hotel on 27 May and are among 14 indicted by the US Department of Justice on charges they received more than $150m (£100m) in bribes.
Swiss authorities have also launched a separate criminal investigation into how the 2018 and 2022 World Cups were allocated.
American lawyer Michael Garcia was previously hired by FIFA to investigate the 2018 and 2022 World Cup bidding processes.
In November, findings from his two-year inquiry were released by FIFA as a summary of his full 430-page report, but Garcia complained their representation of his work was “erroneous”.
The report cleared World Cup hosts Russia and Qatar of wrongdoing.
Garcia quit weeks later over FIFA handling of his inquiry and his comments reopened the debate about the validity of the bidding process.
Scala has since had Garcia’s report reviewed by legal experts both in sport and outside of sport but neither were able to find grounds to alter the award of either tournament at this stage.