French cycling team chief Alain Deloeil has called for checks at this year's Tour de France to ensure that racers are not cheating by using motors hidden in their bike frames.

Recent speculation has focused on Italian rider Fabian Cancellara, who denied this week he won Paris-Roubaix and the Tour of Flanders earlier this year with the help of an electric bike.

Deloeil, sports director of the Cofidis team, said Thursday at the Tour of Luxembourg that checks should be carried out on the Tour to prevent "mechanical doping."

However, former top rider Johan Museeuw says the whole idea of racers using hidden motors was not plausible, even though the technology exists.