The Athletics Integrity Unit (AIU) said a disciplinary tribunal had found that the 30-year-old athlete "bore no fault or negligence" for an anti-doping rule violation resulting from an out-of-competition sample collected by the AIU on December 15 - and therefore he will serve no period of ineligibility.

"The sample was found to contain a low concentration of the specified substance known as acetazolamide (a diuretic)," the AIU said.

"After a thorough investigation of the athlete's explanation during the results management process, the AIU accepted that the positive finding resulted from his unintentional ingestion of residue from medication being used to treat a family member.

"The AIU charge was referred to a three-person panel of the disciplinary tribunal, which found that it was a 'genuinely exceptional' case, accepted the athlete's plea of no fault or negligence and rejected the AIU's request that a period of ineligibility be imposed.

"Accordingly, no sanction has been imposed.

"The full decision will be issued in due course and may be appealed at the Court of Arbitration for Sport."

Shubenkov said his three-month-old son had been prescribed a medication containing the furosemide.

Russian media including Match TV and News.ru had reported that the hurdler was facing a four-year ban having given the sample which was positive for the substance, a diuretic used for weight control that has also been associated with use as a masking agent.

At the time, Shubenkov responded immediately on Instagram.

"Throughout my career, I have never used the forbidden to prepare, I have never deceived anyone," he said.

"I have expressed my attitude towards doping swindlers more than once, and it has not changed.

"All the information about the fact that I used furosemide and that it was found in the sample is blatant slander, invented by an unnamed 'source'.

"This has never happened."

Shubenkov added that he was not under any restriction and was training as normal.

His compatriot Mariya Lasitskene, the three-time world high jump champion, said on Twitter: "When I saw the news about Sergey, I just wanted to sit down and cry.

"But I want to support Sergey.

"Until it's officially proven that he's guilty of something, I refuse to believe the rumours.

"We've been through a lot to end like this."

Shubenkov has been one of the few Russian athletes allowed to compete internationally since the doping ban on the country introduced in 2015 by the sport's world governing body, now known as World Athletics.

After winning the world 110m hurdles title in Beijing in 2015, he missed the following year's Olympic Games in Rio de Janeiro because of sanctions against Russia.

He then emerged as one of the competitors deemed to have shown themselves clean and competed with great success as an authorised neutral athlete.

He won world silver medals at both London 2017 and Doha 2019.

He also took silver at the 2018 European Championships in Berlin, having won European titles in 2012 and 2014.