Turkish athletes Nevin Yanit and Asli Cakir Alptekin have both been charged with doping by the IAAF, and are in jeopardy of losing recently won medals.
Both have been suspended from international competition while an investigation is carried out.
Yanit is twice European 100m hurdles champion – beating Ireland’s Derval O’Rourke into second in the Barcelona Championships in 2010 – and won this year’s European indoors 60m hurdles crown in Gothenburg, a race in which O’Rourke finished fourth.
IAAF spokesman Nick Davies told the Associated Press that Yanit had "multiple positive findings following target tests carried out in-competition and out-of-competition".
Yanit finished 0.02 seconds clear of O’Rourke in those 2010 Europeans, retaining her title last year in Helsinki at a Games that the Cork athlete did not enter.
The Turkish champion went on to enjoy a slender victory over a blanket of athletes in Gothenburg two months ago, with O’Rourke being edged out into fourth place by one-hundredth of a second, narrowly missing out on a fifth Championship medal.
The results have been passed by the world governing body to the Turkish Athletic Federation, but an outcome may not be swift in coming, and there is no indication yet how far back the tests go.
Alptekin is reigning Olympic 1500m champion, having finished ahead of Turkish compatriot Gamze Bulut in the final in London last August.
She is reported to have had abnormal blood values in her biological passport, the system that tracks variations over time in an athlete's blood profile to detect signs of cheating.
Both Alptekin and Yanit were left out of the Turkish team for the upcoming Mediterranean Games, which are being held at the Nevin Yanit Stadium in Mersin.
The statement in full from the IAAF reads:
"The IAAF is now in a position to confirm that both Asli Cakir Alptekin and Nevin Yanit have been charged with anti-doping rule violations by the IAAF.”
"Ms Çakir on the basis of abnormal blood values from her biological passport.
"Ms Yanit on the basis of multiple positive findings following target tests carried out in-competition and out-of-competition by the IAAF.
"Both case have been referred to the Turkish Athletic Federation for adjudication as is usual under IAAF Rules and we await a decision from them.
"Until then, I can confirm that both athletes are now provisionally suspended and cannot compete.
"Again, as is usual under IAAF rules, we will make no further comment until the cases are concluded."