A top Nigerian athlete, Tobi Amusan, says she has been charged with breaking anti-doping rules.
Amusan is the world record holder in the 100m hurdles.
The Athletics Integrity Unit accused her of missing three drugs tests within 12 months.
It could result in a two-year suspension from the sport.
Writing on Instagram, the 26-year-old described herself as a clean athlete.
She said she would fight the charge so that she could compete at the World Championships in August.
BBC
