Cycling's governing body UCI says 2010 Vuelta a Espana runner-up Ezequiel Mosquera and teammate David Garcia both tested positive (non-negative) for a banned substance during this year's race.

The UCI says Mosquera and Xacobeo-Galicia teammate David Garcia showed traces of hydroxyethyl starch - which increases blood volume - in urine samples collected on September 16.

Mosquera won the penultimate stage of the race two days later and finished 41 seconds behind winner Vincenzo Nibali in the overall standings.

The UCI said the riders can request their "B" samples to be analyzed.

Earlier Thursday, the UCI said Tour de France winner Alberto Contador had tested positive for a "very small concentration" of the banned substance clenbuterol during the French classic.