Ukrainian Oleksandr Pyatnytsya has been stripped of the javelin silver medal he won at the 2012 Olympics after a reanalysis of the samples he provided in London uncovered a positive doping test.

Pyatnytsya won silver four years ago, but has tested positive for prohibited substance dehydrochlormethyltestosterone (turinabol).

The International Olympic Committee has ordered the 31-year-old to return the medal he won.

Keshorn Walcott won the gold, with Antti Ruuskanen of Finland set to be promoted into second place and Czech Vitezslav Vesely potentially in for a bronze.

Pyatnytsya was one of four athletes revealed on Tuesday to have provided positive samples at either Beijing 2008 or London 2012.

Weightlifters Nurcan Taylan of Turkey and Hripsime Khurshudyan of Armenia (who both competed in Beijing) and Belarusian hammer thrower Pavel Kryvitski (London) have also been retrospectively disqualified.