MOSCOW (AFP) - Russia's athletics federation said on Wednesday (Jan 17) it was looking into the sudden withdrawal of dozens of athletes from a race, as a report said the mystery was explained by an unexpected visit from doping inspectors.

Thirty-six competitors cancelled their participation in a Siberian track and field championship in Irkutsk after the "anti-doping agency's doping control suddenly showed up," said Russian sports website Championat.com.

Russia's athletics federation confirmed the curious withdrawals at the weekend event.

"The (federation) can report that the federation's disciplinary committee has begun an internal inspection of this fact," it said in a statement.

The federation said it suggested to Russia's anti-doping agency Rusada that it should pay closer attention to regional and junior competitions as "certain problems with doping are present in this segment of Russian track and field."

Championat.com published a list of athletes who were registered to compete but did not participate. Of the 36, 12 reportedly presented a doctor's note, while others simply did not show up.

Russia was banned from international athletics in November 2015 over claims of state-sponsored doping, preventing its athletes from competing at the 2016 Rio Olympics.

Russian athletics federation director Andrei Kruporushnikov said the body "didn't expect" such a result when it suggested that Rusada look into second-tier races.

"We asked Rusada to take all athletes who cancelled under strict control," he told Sport Express newspaper.

But he argued that while lower-level sport has "serious problems", the national team is "the cleanest and most checked in the world".

Rusada was suspended by the world anti-doping agency (Wada) but reinstated last June and has been carrying out doping inspections.

Forty-three Russian athletes were handed lifetime Olympic bans for doping at the 2014 Winter Games, and most are trying to appeal the decision ahead of this year's Games in South Korea.