Sprinter Blessing Okagbare is out of the Tokyo Olympics after being suspended for failing a drugs test.
The Nigerian had won her 100m heat on Friday and was due to race in the semi-finals on Saturday.
The Athletics Integrity Unit (AIU) said the 32-year-old had tested positive for a human growth hormone following an out-of-competition test on 19 July.
The AIU said Okagbare was notified early on Saturday of her provisional suspension on Saturday. It added it would not be making any further comment at this stage.
The 32-year-old, who has also won world championship medals in the 200m and the long jump and is competing in her fourth Olympics, had comfortably won her 100m heat in Tokyo on Friday with a time of 11.05 seconds, qualifying for Saturday’s semi-final.
The AIU ruled they were unable to take part because of non-compliance with out-of-competition drug testing requirements in the run-up to the Olympics.
This is the latest blow for Nigeria’s athletics team after 10 track and field athletes were ruled as ineligible for the Tokyo Games three days ago for failing to meet minimum testing requirements.
On the list of banned substances, human growth hormone reduces body fat, increases muscle mass and strength and helps in recovery, according to the World Anti-Doping Agency.
Meanwhile, the Athletics Federation of Nigeria (AFN) has received with great shock, the press release by the Athletics Integrity Unit, suspending Blessing Okagbare for a doping test violation.
President of the Federation, Tony Okowa said in short statement early on Saturday that Nigeria is in the process of obtaining the relevant details of the announcement after which a full react will be issued.