Athletics chiefs have been criticised for denying a medal favourite entry to London Stadium amid attempts to control an outbreak of norovirus at the World Athletics Championships.
Botswana’s Isaac Makwala, 30, had hoped to run in Tuesday’s 400m final.
He was earlier withdrawn from the race on medical grounds by officials from the sport’s governing body, the IAAF.
“The manner in which this decision was arrived at is disturbing,” said Botswana Olympic boss Falcon Sedimo.
Public Health England says 30 athletes and support staff have been affected by sickness at the Tower Hotel in London – though the hotel is not the source of the outbreak.
The International Association of Athletics Federations (IAAF) has insisted it gave clear communication to the Botswana delegation that Makwala would not be allowed to run following a medical examination.
But Botswana Olympic Committee CEO Sedimo told BBC Sport: “There has been no official communication, no formal communication from the IAAF at all. We found out from the media that he could not take part and he is heartbroken.
“There have been no medical tests at all, it’s just generalised assumptions because of the outbreak of sickness and he has just one of those symptoms.”
Botswana medical team member Simon O’Brien said Makwala showed no symptoms of the bug and blamed “poor communication” from the IAAF for Makwala missing the race.