Ukraine's former European champion Oleksandr Pielieshenko is among two athletes to have failed a drugs test, the International Weightlifting Federation (IWF) has announced.
The 24-year-old has tested positive for chlorthalidone, a medication used to treat high blood pressure.
Armenia's Sona Poghosyan has also failed a test, the IWF said.
Both athletes who have failed have competed at the Olympic Games.
Pielieshenko now faces a lengthy ban after previously serving a two-year suspension between 2013 and 2015 due to a failed test for stanozolol.
The Ukrainian, who has been provisionally suspended, won the overall title in the men's under-85 kilograms division at the European Championships in both 2016 and 2017.
He also won clean and jerk gold in 2016 and the snatch title a year later.
However, he could not add further success at this year's European Championships in Romania, which concluded yesterday, as Ukraine is one of nine nations currently serving a one-year ban issued by the IWF.
All nine had three or more of the 49 positives revealed when the International Olympic Committee (IOC) retested samples from the 2008 and 2012 Olympic Games in Beijing and London using up-to-date technology.
"The athlete is provisionally suspended in view of a potential anti-doping rule violation," an IWF statement said.
"In any case where it is determined that the athlete did not commit an anti-doping rule violation, the relevant decision will also be published.
"IWF will not make any further comments on the case until it is closed."
News of Poghosyan's positive comes after allegations of widespread cheating in Armenian weightlifting emerged in the media last week.
She has failed for GHRP-2, a growth hormone, and has also been provisionally suspended.
The Armenian won overall bronze in the under-75kg class at the 2017 European Championships.
Weightlifting has been warned by the IOC that it must address its doping problem if it is to retain its place on the Olympic programme at the Paris 2024 Games.
The IWF say they have adopted a new "hard-line" approach to doping but the IOC has placed the sport on probation and has asked for a report by June which needs to prove that plans can be implemented.
As well as Ukraine, Russia, Kazakhstan, Armenia, Azerbaijan, Belarus, Moldova, China and Turkey are all serving one year bans.