Paris - Doping investigators may stage night-time raids to test Tour de France riders, says international cycling union president Brian Cookson.
"It is a possibility. No team should think that they can escape at this level," Cookson, whose federation gets some of the closest anti-doping attention in the world, told Le Monde newspaper.
A new World Anti-Doping Agency (WADA) code of conduct allows tests on athletes "at any time".
The code is not yet effective in France however, because of a debate over the legal terms used, which could make a night raid controversial. A government decree is not expected until after the cycle race finishes.
The French anti-doping agency, the AFLD, is responsible for Tour de France tests on behalf of the UCI's independent anti-drugs foundation.
"Night-time controls are not allowed by French law at the moment," said AFLD president Bruno Genevois.
"But one should not be dogmatic on the topic. There are not only tests. We can work with the gendarmerie and the customs service if there is information that suggests irresponsible behaviour," he added.
"We are allowed to do tests from 06:00 and if we have information we can rely on the customs and the gendarmes," Genevois said.