Nigerian sprinter Osayemi Oludamola, who won the women's 100m gold at the Commonwealth Games, has failed a drugs test and could be stripped of her gold medal.
Commonwealth Games Federation president Mike Fennell confirmed that Oludamola had failed a test for the stimulant methylhexaneamine at the start of today's daily media briefing in Delhi.
Oludamola has been provisionally suspended. She requested the testing of her B sample and that test will be followed by a hearing this afternoon.
Fennell said: "We have conducted over 950 drugs tests and I have to report that we have had a positive result.
"That result was in relation to the winner of the 100 metres final, the Nigerian Osayemi Oludamola.
"She has been notified in accordance with the anti-doping standard that applies to the Games.
"She has requested the testing of the B sample. The B sample will be tested by the laboratory today and hearing will be held later today."
Asked what damage the failed test would do to the reputation of the Games, Fennell replied: "Any positive test, whether it is in a high profile event or not, is to be regretted because we are striving for a clean Games and clean competition.
"We don't know what damage this will cause the Games but I want to assure everyone that we are being vigilant and the testing is of the highest standard."
Delhi 2010 organising committee general secretary Lalit Bhanot said: "We want a dope-free Games. If somebody is caught, action will be taken. At the same time it is a message that no-one can escape."
The World Anti-Doping Agency (WADA) recently loosened the classification of methylhexaneamine for next year to the specified stimulant list, which covers drugs that are more susceptible to inadvertent use and can carry reduced penalties.
Sanctions for use of the drug can be reduced if athletes can prove they did not intend to enhance performance by taking them and penalties can range from a warning to a two-year ban.
Australian Sally Pearson crossed the line first in Thursday night's controversial final but was later disqualified for a false start and Oludamola was promoted from silver to gold.
Natasha Mayers of St Vincent and the Grenadines moved up to silver and and England's Katherine Endacott was awarded the bronze, while team-mate Laura Turner was also disqualified for a false start.
England and Nigeria appealed the original result, which saw Pearson named champion, and their protest was taken to the competition's jury of appeal.
A counter-protest from Australia was then unsuccessful, meaning Pearson joined Turner in being disqualified.
If Oludamola is stripped of her gold medal Mayers would be promoted to gold, Endacott to silver and Cameroonian athlete Bertille Delphine Atangana, who finished fourth, to bronze.
Fennell was asked if any decision had been made on Oludamola's gold medal.
He said: "There was a positive test. At the moment no decision has been made on the medals.
"There is a provisional suspension and her hearing will be held this afternoon."
Fennell promised that the outcome of Oludamola's hearing would be issued to media later today.
"We have been very transparent and up front on this. When the hearing has been concluded we will issue the results.
"We recognise that there is difficulty in maintaining complete secrecy until after the process has been completed in these cases so, after the athlete has been notified, we make a public announcement."