"The International Olympic Committee (IOC) officially informed the Russian Olympic Committee that the results of new samples taken during the London Olympic Games have returned positive results for eight Russian athletes in three disciplines," the ROC said in a statement after the IOC on Friday reported 23 new doping failures from retests on 265 samples from London.
Russia this week confirmed that 14 of their athletes were found to be positive in the 2008 Beijing Olympics after retesting.
The head of the ROC's legal department, Anna Brilliantova, said the B samples would be tested on May 31 and June 1 at the anti-doping laboratory in Lausanne, Switzerland.
The Russian athletics federation said on Tuesday that it would bar any athlete found to have used doping in previous years from competing at Rio.
The latest revelations come as Russia is embroiled in an immense doping scandal which could prevent its track and field athletes from competing in Rio.