Russian news agency Tass reported the coach of Marina Shainova saying her B sample, and that of Nadezhda Evstyukhina, 28, have tested positive.
Vladimir Shainov said: "Certainly, her medal will be taken away and she will be disqualified. Evstyukhina is in the same situation."
Shainova, 30, won a silver medal and Evstyukhina a bronze at Beijing 2008.
Two Russian female weightlifters face being stripped of their Olympic medals after positive drug tests.