Alexander Povetkin has tested positive for meldonium ©Getty Images

Russian boxing star Alexander Povetkin has shown traces of meldonium in a doping sample and faces being forced to pull out of his World Boxing Council (WBC) title fight with American rival Deontay Wilder next week.

The 36-year-old heavyweight, a gold medal winner at the Athens 2004 Olympics, returned "low concentrations" of the substance in a blood sample in April, a spokesperson told the TASS news agency.

It will now be up to the WBC to decide whether his fight with Wilder in Moscow on May 21 can go ahead.

He becomes the latest leading Russian athlete to fail for the recently banned substance in a list headed by tennis superstar Maria Sharapova.

Meldonium was added to the World Anti-Doping Agency’s (WADA) prohibited list on January 1 after they found “evidence of its use by athletes with the intention of enhancing performance”.

But the body have since admitted that more research is required about how long the product stays in the system after being taken, and admit that, if below one microgram of the substance was detected in a test before March 1, a no fault or negligence verdict can be reached.

Andrei Ryabinsky, the head of Mir Boksa promotions, described the situation as "ambiguous".

"He consumed it [meldonium] in September last year," he told TASS.

"He has not taken it since 1 January."

Players from Russian football team FC Rostov have also been linked with meldonium this week ©Getty Images
Players from Russian football team FC Rostov have also been linked with meldonium this week ©Getty Images

Ryabinsky claimed his sample contained just 70 nanograms, or seven per cent of what the anti-doping authorities banned, adding that "politics has intervened in boxing".

World Boxing Council President Mauricio Sulaiman told R-Sport today an official statement on the fight would come within 24 hours once the organisation receives confirmation of the news.

If confirmed, the result would be another blow for boxing after Australian Lucas Browne was stripped of his World Boxing Association (WBA) heavyweight title after both his "A" and "B" samples tested positive for banned substance clenbuterol.

It comes as a fresh meldonium scandal has emerged surrounding football club FC Rostov as they continue their surprise pursuit of the Russian Super League title.

Rostov, who only remained in the Russian top flight after a relegation playoff last year, have strongly denied rumours and claim all 11 of their starting team were tested by an unannounced FIFA team after a 3-1 win against Dynamo Moscow last week.