Several athletes who competed in the world championships in August have tested positive for the new designer steroid THG, a spokesman for the International Association of Athletics Federation said today.
Retesting on 400 urine samples taken during the championships in Paris were not yet complete, but with about 75 percent of the results now in "a very small number" had tested positive for the previously undetectable drug.
The final number will be announced on Saturday at an IAAF council meeting in Berlin but no names would be given.
"So far there are no surprises," the IAAF spokesman Nick Davies said. The athletics governing body has said it does not believe THG use to be widespread.
However, five athletes, including European 100 metres champion Dwain Chambers of Britain, tested positive for the drug which until this year had been undetected.
The other four have yet to be officially confirmed.