A male weightlifter from Kyrgyzstan became the first athlete at the Rio de Janeiro Olympics to be stripped of a medal after a positive drug test. A Moldovan canoeist also risks losing his bronze medal after being suspended for alleged doping.

Weightlifter Izzat Artykov tested positive for strychnine after winning the bronze medal in the 69-kilogram division, the Court of Arbitration's anti-doping division said Thursday.

The 22-year-old lifter's medal was taken away and he was kicked out of the games.

Strychnine is a defined as a stimulant in the World Anti-Doping Agency's list of banned substances.

It is a highly toxic drug often used as a pesticide, particularly for killing rodents. However, it also has a long history in sports doping, used in small doses to tighten tired muscles. Strychnine was reportedly commonly used in the early years of the Tour de France to help cyclists survive the demanding rides.

CAS referred the case to the international weightlifting federation for possible further sanctions against Artykov, who could face a two-year ban from the sport. The federation and the IOC were asked to decide on the reallocation of the medal.

Luis Javier Mosquera of Colombia is in line to be upgraded from fourth place to the bronze medal. China's Zhiyong Shi won the gold and Turkey's Daniyar Ismayilov took the silver.

Also Thursday, the International Canoe Federation said that canoeist Serghei Tarnovschi of Moldova had been suspended after failing a pre-competition doping test.

The 19-year-old Tarnovschi placed third in the 1,000 meters canoe single final Tuesday and was due to compete in the 1,000 meters double on Friday with his older brother, Oleg.

In a brief statement, the ICF said he will "now no longer be eligible and will face provisional suspension" under anti-doping rules.

ICF spokesman Richard Pettit told The Associated Press that Tarnovschi's medal had been removed pending the outcome of a hearing.

Pettit declined to say what Tarnovschi was accused of taking.

Ilya Shtokalov of Russia placed fourth in the event and is in line for the bronze if the medal is reallocated.

The Belarus men's team and the entire Romanian team were excluded from the canoe sprint competition before the games due to widespread doping.

Last week, Polish weightlifter Tomasz Zielinksi and Bulgarian steeplechaser Silvia Danekova were kicked out of the games after testing positive for banned substances, while Chinese swimmer Chen Xinyi accepted a "provisional suspension" after testing positive for a diuretic.

Several other positive tests are in the process of being heard by CAS, which is handling doping cases at the Olympics for the first time. The International Olympic Committee handed over responsibility to CAS to try to make the process more independent.