The runners were targeted in pre-competition tests at their team hotel in Beijing on Aug. 20 and 21, the IAAF said in a statement.

The IAAF has spent the last month defending itself against accusations that it is soft on doping after data from thousands of blood samples were leaked to the media.

While critics of the IAAF might point to the positive tests as further evidence of widespread doping in the sport, the governing body is likely to see this as proof that their targeted testing is effective in weeding out drug cheats. Zakary, 29, ran a Kenyan record of 50.71 in the heat of the 400 metres in Beijing but failed to start the semi-final.

Manunga, 21, finished sixth in her heat in the 400 hurdles last Sunday and failed to progress to the next round.  

--reuters--