UEFA challenged a former football official Monday to prove his claim that the 2012 European Championship was corruptly awarded to Poland and Ukraine, or risk a defamation suit.
European football's ruling body said it has set a Wednesday deadline to receive evidence after making ''repeated requests'' to Cyprus Football Association board member Spyros Marangos for information.
Germany's Sueddeutsche Zeitung newspaper reported allegations by Marangos that high-ranking UEFA officials sold the tournament for ?11 million ($15 million).
''In relation to this as-yet-unsubstantiated claim, UEFA wishes to state that, as always, it can only open an investigation on the basis of tangible elements of proof,'' UEFA said in a statement. ''To date, these have never been provided to UEFA by this individual.
''If no such evidence is submitted within the time frame, UEFA reserves its right to start legal proceedings, civil and criminal, against any individual or individuals making such defamatory statements.''
Officials from Poland and Ukraine deny the claims.
The eastern European neighbors were awarded Euro 2012 hosting rights by beating Italy in a poll of UEFA Executive Committee members in 2007.
