Four Russian gold medallists in Sochi reportedly doped

The hosts Russia won 13 gold medals at the Sochi Winter Olympics

Russian doping whistleblower Vitaly Stepanov alleges in an interview for an upcoming edition of CBS television's "60 Minutes" that four of the country's gold medallists at the 2014 Sochi Olympics doped.

In an interview to air today, Stepanov, a former official with the Russian Anti-Doping Agency (RUSADA), cites Grigor Rodchenkov, former head of Russia's now-discredited drug testing lab, as telling him that FSB state security service officers "tried to control every single step of the anti-doping process in Sochi".

Hosts Russia won 13 gold medals at the Sochi Winter Olympics.

A brief preview of the interview released by CBS reveals no names of suspected dope cheats.

But the story could signal a widening of the doping scandal that has engulfed Russian athletics, with the country's track and field stars facing a ban from the 2016 Rio Olympics in August.

Stepanov and his wife, banned athlete Yuliya Stepanova, appeared in a German television documentary claiming systematic doping in Russian athletics in 2014 -- allegations later supported by an investigation by a World Anti-Doping Agency (WADA) independent commission which found evidence of "state-sponsored" doping and widespread corruption.

The International Association of Athletics Federations (IAAF) suspended Russia in November, with the IAAF council due to decide in June if the country's athletes can compete in Rio.

In the "60 Minutes" programme, US Anti-Doping Agency Chief Travis Tygart says he doesn't believe Russian athletics has done enough to warrant reinstatement and USADA is "not in favor" of Russian athletes competing in Rio.

"They can't come at the expense of clean athletes' rights," he tells "60 Minutes".