"The UCI has not to date received any official information or document" from anti-doping authorities or the laboratory reportedly involved in the testing of urine samples from the 1999 Tour de France, the UCI said.
Allegations that EPO was found in Armstrong's 1999 urine samples were first reported by the French sports daily L'Equipe last month.
Armstrong, who has won the Tour a record seven times, has angrily denied the charges and questioned the validity of testing samples frozen six years ago, how those samples were handled since, and how he could be expected to defend himself when the only confirming evidence no longer exists.
UCI said it was still gathering information and had asked the World Anti-Doping Agency and the French laboratory for more background. Most importantly, it wanted to know who commissioned the research and who agreed to make it public.
"We have substantial concerns about the impact of this matter on the integrity of the overall drug testing regime of the Olympic movement, and in particular the questions it raises over the trustworthiness of some of the sports and political authorities active in the anti-doping fight," the UCI said.
UCI president Hein Verbruggen has demanded more severe sanctions for dopers and suggested Armstrong should face sanctions if doping was proved. He also told Friday's Le Figaro that Armstrong had proposed before the Tour that all of his urine samples be kept for tests over the next 10 years.