ATHENS, Aug 27: Anti-doping authorities were trying to track down Olympic champion Adrian Annus on Friday amid suspicions the Hungarian may have duped drug-testers after winning a gold medal in the hammer throw.

Annus, who announced his retirement from the sport on Friday, left Greece immediately after striking gold in the hammer on Sunday. Mandatory drug tests carried out on the athlete after the event were negative.

But following the controversy over Hungary's discus champion Robert Fazekas - who was stripped of his Olympic gold medal for failing to provide a urine sample - questions have now been raised over his friend Annus.

International Olympic Committee (IOC) President Jacques Rogge confirmed that the athlete was being sought by drug-testers. IOC sources believe there may be a possibility that Annus conned testers in Athens by providing a sample of urine that was not his own.

They now want to test the 29-year-old again to compare the genetic make-up of his urine with that submitted during official testing at the Olympics. If the two samples do not match, Annus will be charged with an anti-doping violation and stripped of his gold medal, IOC sources told AFP.

Yet the whereabouts of Annus remained a mystery on Friday after he failed to appear for a drug test carried out by the Austrian Anti-Doping Committee (OADC) on the Austrian-Hungarian border.

The IOC and the World Anti-Doping Agency (WADA) had both been informed of the missed test, which could lead to a suspension from the sport. Any suspension could now be rendered redundant however after Annus announced his retirement in a statement released in Hungary.

"I am ending my career," Annus said in the statement, adding that he undergone numerous tests during the Olympics "all of which had been negative." "The World Anti-Doping Agency tested be a number of times. And each time I willingly complied with the procedure.

"I have a clear conscience because I know that I have never taken illegal substances." Annus won the gold ahead of Japan's Koji Murofushi. -AFP