LONDON (Reuters) - Russian drug cheats will be competing at next month's Rio Olympics, the whistleblowers who helped uncover the country's doping scandal have told the BBC.

Vitaly Stepanov, who worked for Russia's anti-doping agency, and his wife, former drugs cheat Yulia Stepanova, helped lift the lid on Russian doping in a series of documentaries by German broadcaster ARD.

Their evidence led to a report commissioned by the World Anti-Doping Agency, which uncovered widespread doping in Russian athletics, and was followed by the McLaren report.

The latter found Moscow had concealed hundreds of positive doping tests in many sports ahead of the Sochi winter Games.

However, the International Olympic Committee (IOC) decided not to impose a blanket ban on Russia competing in Rio.

The Stepanovs said on Tuesday that the IOC's stance of leaving governing bodies to decide whether Russians could take part in the Games meant there would be Russian athletes in Rio whose cheating had previously been covered up.

"Others that have been covered up over the past years by the Russian sports authorities, they will compete as supposedly clean athletes," the pair said in a joint BBC interview.

"As the report said it involved 20 summer Olympic sports, this system of cover ups, so yes there will be athletes who have used doping from Russia in Rio."

The couple have fled Russia and are living in hiding at an undisclosed location in North America, after they provided evidence of doping.

The IOC decided on Sunday not to impose a total ban on Russian competitors despite the country's doping history.

They asked sports federations, however, to stop Russian athletes from competing in Rio who were implicated in the McLaren report, or had been previously sanctioned.

This dashed Stepanova's hopes of running at the Games as an independent athlete, which Vitaly said was unfair.

"You didn't really have a choice if you wanted to be a member of the national team," he said.

"She has served her ban, fully served her ban, she thinks that she should not be punished a second time for something that she did in the past."

(Reporting by Toby Davis; Editing by Ken Ferris)