TOKYO (AP) — Twenty athletes, including 10 from Nigeria, will not be allowed to participate in track and field at the Olympics because they did not meet anti-doping testing requirements in the lead-up to the Games.

Athletes from countries categorized as “high risk” because of deficiencies in their anti-doping programs have to be given three no-notice, out-of-competition tests in the 10 months leading to a major event.

Each of the seven so-called “Category A” countries had at least one athlete banned from the Games.

The countries are Belarus, Bahrain, Ethiopia, Kenya, Morocco, Nigeria and Ukraine.