Two world champion weightlifters and an Olympic gold medalist are among four Thai weightlifters to test positive for banned steroids, the International Weightlifting Federation announced on Tuesday.

Thunya Sukcharoen and Sukanya Srisurat risk being stripped of the world titles they won in November after each testing positive for at least one anabolic steroid and artificial testosterone. If found guilty, Sukanya faces a potential eight-year ban for a second offense.

The 2016 Olympic champion at 48 kilograms, Sopita Tanasan, also tested positive after finishing fourth at the world championships. Sixth-place finisher Chitchanok Pulsabsakul also failed a drug test.

The failed tests are another embarrassment for weightlifting, which is under pressure from the International Olympic Committee to crack down on doping. Weightlifting is on the Olympic program for next year’s games in Tokyo, but only provisionally for 2024.