(Reuters) - The International Cycling Union (UCI) carried out 3,773 tests for mechanical doping during this year's Tour de France and none proved positive, the UCI said on Wednesday.

Random tests were carried out before, during and after racing during the 21 stages of the three-week event and all were negative.

The tests showed an "absolute commitment to leave no stone unturned," UCI president Brian Cookson told the ruling body's website.

"We will continue to test bikes heavily throughout the rest of the season, and do everything in our power to make sure this form of cheating stays out of our sport."

The UCI began using a new system to scan for hidden motors in January and more than 10,000 bikes have since been tested.

Only one test proved positive, on Belgian Femke van den Driessche at the 2016 Cyclo-Cross world championships. She was banned for six years and fined 14,000 pounds ($18,400).

(Reporting by Ed Osmond; Editing by Toby Davis)