The suspension of several athletes in Russia's dominant race-walking team has drawn an investigation by the Russian Anti-Doping Agency.
RUSADA said on Friday it opened "a preliminary investigation into possible breaches of anti-doping rules in relation to athletes' staff" because of "multiple disqualifications of athletes."
RUSADA requested biological passport data on athletes from the IAAF.
The move followed an online campaign led by Australian Olympic walking medallist Jared Tallent against Russia coach Viktor Chegin, who Tallent says has overseen 17 of his athletes banned for doping.
The latest was reigning Olympic 20-kilometre champion Elena Lashmanova, who was suspended for two years last month after testing positive for banned substance GW1516.
Lashmanova was also the world champion and 20K world record-holder.
Anti-doping authorities last year warned athletes against taking GW1516 after it was found to rapidly cause multiple cancers in rats.
Among prominent Russian race-walkers to have been banned was men's 20K world record-holder Vladimir Kanaykin, who was one of a group of five Russian walkers to receive two-year bans for failing drug tests shortly before the 2008 Beijing Olympics. He has since returned to competition.
Another of those five, Sergei Morozov, was banned for life in 2012 for a second doping violation, but was allegedly pictured serving on the Russian team's staff at the World Race-Walking Cup in May.
Last month, IAAF vice-president Sergei Bubka said on Twitter that it was "looking into" claims of malpractice in the Russia team following Tallent's campaign, and that the IAAF race-walking committee "raised strong concern."
Bubka, the pole vault great, said he would raise the issue when the IAAF council meets in Eugene, Oregon, during the world junior athletics championships this month.
