Dozens of Russian athletes withdrew from the Siberian Indoor Championships last week following the arrival of drug testers.

As many as 36 athletes dropped out of the meet in Irkutsk, with many citing illnesses as the reason for their sudden withdrawal, according to the Associated Press. The Russian track and field federation said it's investigating the mass exodus.

The federation launched a similar investigation last year when five athletes withdrew from a track and field competition in Orenburg, leaving one women's race with just three finishers.