Krol, née Pryshchepa, was found to have tested positive for the banned diuretic hydrochlorothiazide.

She has now been provisionally suspended by the AIU and faces the prospect of a ban.

Krol claimed the gold medal in the women’s 800m at the 2016 European Athletics Championships in Amsterdam.

She won the event in 1min 59.70sec, with France’s Renelle Lamote and Sweden’s Lovisa Lindh completing the podium in 2:00.19 and 2:00.37.

Krol retained the title two years later in Berlin, where she triumphed in 2:00.38.

Lamote again finished as the silver medallist by finishing in 2:00.62, while Ukraine’s Olha Lyakhova was third in 2:00.79.

Krol was also named as the winner of European Athletics’ Fair Play award in 2018, after helping console Belgium’s Renee Eykens, who fell in the home straight during the heats at the Championships.

The 25-year-old is currently ranked 21st in the world rankings for the women’s 800m.

A ban would rule Krol out of competing at a second Olympic Games.

She was a member of Ukraine’s team at Rio 2016, where she advanced to the semi-finals of the women’s 800m.

Krol failed to advance to the final after placing fourth in her semi-final.