Kenya's Emmaculate Anyango, the world's second fastest woman over 10km, has been provisionally suspended after a failed doping test, the Athletics Integrity Unit (AIU) said on Friday.
The 24-year-old Anyango faces a ban of up to four years after testing positive for prohibited testosterone and the banned blood-boosting hormone EPO.
An African U20 3,000m silver medallist in 2019, Anyango has been tipped as one of the East African nation's rising stars.
She became the second Kenyan woman to run 10km in under 29 minutes, finishing runner-up in Valencia in January behind compatriot Agnes Jebet Ngetich who won with a world record 28:46.
Anyango also defied a strong field that included former New York and London marathon champion Joyciline Jepkosgei to win the women's cross-country race at Sirikwa Classic, a World Athletics Tour Gold meeting in Kenya's northwest in February.
Kenya has invested massively in the wake of a doping scandal at the 2016 Rio Olympics, creating its revamped anti-doping agency that year. Some 78 athletes have been sanctioned in the last three years alone.
In June Kenya's 10km road race men's record holder Rhonex Kipruto was banned for six years for doping and his world mark cancelled by the AIU.
However, there are fears the programme could be undermined after the Anti-Doping Agency of Kenya said last month that severe budget cuts had halted tests.