The World Anti-Doping Agency (WADA) is reportedly allowing athletes a trace amount of the banned drug meldonium which could clear athletes who have tested positive for it.

The announcement came as it remains unclear how long the substance remains in the system. WADA announced last autumn that meldonium would be placed on the banned-substance list as of January 1.

A total of 172 athletes, led by Russian tennis star Maria Sharapova, have since tested positive for meldonium and are suspended.

WADA sent a statement to national anti-doping agencies providing "clarification" on its inclusion on the prohibited list, notice of existing and continuing studies on its excretion from the body and the results management and adjudication process.

It has led to reports that suspended athletes who took in the substance before January 1 could be cleared and for instance compete at the Rio de Janeiro Olympics in August.

It is believed this could apply to athletes with a concentration of under 1 microgram of meldonium per millilitre in test samples collected before March 1.

Up for further review to determine the time of the intake are cases of athletes with concentrations of up to 15 micrograms in tests before March 1, and with less than 1 microgram in tests after March 1.

"There is no doubt as to the status of meldonium as a prohibited substance," WADA president Sir Craig Reedie said.

"There is equally no doubt that the principle of strict liability under the code; as well as, the well established process for results management and adjudication prevail."

He said that since meldonium was added to the prohibited list on January 1 there have been 172 positive examples, but WADA has been asked for further clarification and guidance from its stakeholders,

"WADA recognizes this need - that meldonium is a particular substance, which has created an unprecedented situation and therefore warranted additional guidance for the anti-doping community," he said.

The WADA statement added: "There is currently limited data available on excretion studies relating to meldonium; and, as such, several studies are currently being conducted involving WADA accredited laboratories, which WADA will share when available."

On Friday, Russia's sport minister Vitaly Mutko threatened to take legal action against the WADA if it did not provide a grace period for Russian athletes who used meldonium before it was banned.

The governing biathlon body IBU last week suspended proceedings against two Ukrainian athletes until the results of studies on how long meldonium remains in the system.

Mutko on Wednesday welcomed the WADA release but told Rossiya 24 TV it is "premature" to speak of an amnesty.

"This is only a recommendation from WADA, which held a research and found out that one of the peculiarities regarding meldonium is that it takes up to two months for the substance to leave the body system.

"The drug, however, could remain in the body system much longer depending on the consumed dose. It also depends on the schedule of the drug’s consumption and physical peculiarities of each individual body. Each case is individual and must be treated separately."

The drug was developed by Soviet/Latvian Ivars Calvins to aid blood circulation, and is mainly produced in Latvia.

German anti-doping expert Fritz Soergel meanwhile told dpa scientific research has shown that the substance does not stay in the system very long.

Soergel questioned why meldonium was added to the banned list in the first place.

"There is not much in scientific literature which qualifies this substance as a doping substance. For me it is a nutrition supplement, at most," Soergel said.

The International Tennis Federation (ITF) meanwhile would make would make no comment Wednesday on the Sharapova case, citing confidentiality.

Sharapova is currently suspended and is due a hearing with no date yet made public. It is believed it will be held before the end of this month.

ITF president Dave Haggary criticiized WADA, saying: "The fact that WADA felt compelled to issue this unusual statement now is proof of how poorly they handled issues relating to meldonium in 2015.

"Given the fact that scores of athletes have tested positive for taking what previously was a legal product, it's clear WADA did not handle this properly last year and they’re trying to make up for it now."

Related stories

Latest news

Syrian opposition rules out future role for President al-Assad

The Syrian opposition said Friday it would not accept any role for President Bashar al-Assad in the future of the war-torn country, reacting to a recent US shift saying that removing al-Assad is no longer a priority for Washington.

Russian Army integrates breakaway forces of Georgian province

Parts of the small fighting forces of the Georgian breakaway province of South Ossetia have been placed under Russian military control, Russian Defence Minister Sergei Shoigu said on Friday.

Czech Republic's Pilsner Urquell beer is now Japanese

Japanese brewing company Asahi completed its takeover of the Czech brewery Pilsner Urquell on Friday, Asahi said in a statement.

Judge approves 25-million-dollar settlement of Trump University case

A US district judge on Friday approved a 25-million-dollar settlement of lawsuits and state fraud allegations against Trump University, the US president's now-defunct business venture.

Former Thai premier Thaksin to junta on reconciliation: 'Cut me out'

Former Thai prime minister Thaksin Shinawatra on Friday announced that he is not interested in the junta-led reconciliation process, three days after the junta handed him a half-a-billion-dollar tax bill for his past business deal.

Dalic: We welcome possible deal between Agrokor and banks

The government welcomes the possibility of an agreement being concluded between the Agrokor food company and creditor banks, and the bill on vitally important companies is not a fallback plan but the result of the government's care for the overall economic and financial stability of Croatia, Deputy Prime Minister and Minister of Economy Martina Dalic told a press conference in Zagreb on Friday.

Croatia, China sign action plan for cooperation in agriculture

The Croatian and Chinese ministries of agriculture on Friday signed an action plan for cooperation in the field of agriculture for the period 2017-2018, the Croatian ministry said in a statement.

ZSE indices up, Agrokor shares in focus of investor interest

The Zagreb Stock Exchange (ZSE) indices on Friday rose by more than 1.8%, with stocks of the Agrokor food and retail concern being in the focus of investor interest again.

Berlin police defend handling of Berlin market attacker

Berlin police defended themselves on Friday against accusations that they stopped surveillance on Berlin Christmas market attacker despite knowing in June 2016 he was dangerous.

Croatia, creditors tailor emergency measures to save tottering giant

Croatia's tottering retail and food giant Agrokor reached an agreement with its creditors, putting its debts standby and allowing it to continue working during emergency restructuring, the Croatian branch of Austria's Erste Bank said Friday.

Agrokor's creditors say standstill agreement to go into force today

A standstill agreement regarding the Agrokor concern's existing financial obligations to banks will take effect on Friday, additional capital will be injected into the concern in the coming days and the concern will be actively restructured, which includes a change of its management, it was said on Friday after a meeting between Agrokor's suppliers and creditor banks.

Palestinians, UN slam Israel's new settlement plan

Palestinians, Israeli activists and the UN lambasted the government of Israeli Prime Minister Benjamin Netanyahu on Friday, a day after it gave the go-ahead for the first new West Bank settlement in a quarter of a century.

South Sudan rebels release three abducted foreign oil workers

South Sudanese rebels have released three foreign engineers they abducted in early March in the oil-rich Upper Nile region, Foreign Affairs Ministry official Mawein Makol Arik said on Friday.

Turkish opposition: Imprisoned party chief has gone on hunger strike

The head of Turkey's pro-Kurdish opposition party has launched a hunger strike from prison.

European leagues threaten Champions League schedule clashes

The European Professional Football Leagues (EPFL) on Friday threatened schedule clashes on Champions League matchdays in an ongoing dispute with the governing body UEFA.

Danish court revokes citizenship of IS volunteer

A Danish appellate court on Friday stripped a man of his Danish citizenship for volunteering to fight for the extremist Islamic State in Syria.

Banks and Agrokor agree on key elements of standstill agreement

Member banks of the coordinating committee of financial creditors and representatives of the Agrokor food company have in principle agreed on key elements of a standstill agreement, which is expected to be signed later today, announcing changes in the company's management team, Erste Bank said in a statement on Friday afternoon.

Syrian man on trial in Sweden; mosque attack labelled terrorism

A Syrian man went on trial Friday in the southern Swedish city of Malmo, charged with terrorism and arson after an attack last year on a building used as an assembly hall by Shiite Muslims.