Three female weightlifters from Kazakhstan have been stripped of the Olympic gold medals they won at London 2012 after testing positive for banned substances.

The International Olympic Committee (IOC) on Thursday confirmed that eight athletes who competed in London have been sanctioned following re-analysis of samples taken from Games four years ago.

Zulfiya Chinshanlo, winner of the women's under-53 kilogram weightlifting event in the English capital, has been disqualified after testing positive for oxandrolone and stanozolol.

Fellow Kazakh Maiya Maneza must also hand back the gold medal she was presented with in the under-63kg category after it was revealed she took stanozolol.

Svetlana Podobedova tested positive for the same substance, so the IOC has ordered the return of her under-75kg gold.

Belarusian Marina Shkermankova has been stripped of her under-69kg weightlifting bronze after traces of turinabol and stanozolol were found in her sample.

Shkermankovas' compatriots - and fellow weightlifters - Dzina Sazanavets and Yauheni Zharnasek have also been disqualified.

Russian athletes Dmitry Starodubtsev and Kirill Ikonnikov, who competed in the pole vault and hammer respectively, have been sanctioned after testing positive for turinabol.