The China Anti-Doping Agency on Tuesday urged the United States to stop fabricating false narratives, politicizing anti-doping, manipulating public perception and embracing double standards when dealing with doping cases of athletes from the US and other countries, including Chinese swimmers.

The remarks came after recent media reports questioned the procedures carried out by the United States Anti-Doping Agency as it examined an adverse analytical finding case of US sprinting star Erriyon Knighton, a member of the US Olympic track and field team, and the conclusion the agency made.

Knighton, 20, tested positive for performance enhancer trenbolone, a banned steroid, during an out-of-competition test on March 26. But the USADA decided before the start of the domestic qualifiers for the Paris Olympics that no ineligibility would be imposed on Knighton, claiming that the athlete's positive result for trenbolone was caused by his ingestion of contaminated meat, and allowed him to eventually represent the US at the Paris Olympics, CHINADA said in a statement published on Tuesday.

On Monday, Knighton qualified for the semifinals of the Men's 200m at the Paris Olympics.

In fact, trenbolone is an anabolic agent with strong enhancing effects on strength and explosiveness, and is not a common contaminant. Hundreds of AAF cases for trenbolone have occurred around the world in recent years, and publicly available information shows that athletes involved in most anti-doping investigations involving the drug were essentially given four-year bans.

In Knighton's case, the independent arbitrator concluded that the contaminated meat in this case came from a restaurant in Florida.

For reasons unknown, the USADA didn't start its investigation into his until two months after the finding, and it happened to detect trenbolone in a different batch of beef purchased from the same restaurant, the CHINADA statement said.

The agency also didn't warn other American athletes about the contamination or carry out studies on how much contaminated meat can cause a positive test, it said.

Later, USADA CEO Travis Tygart publicly declared in a statement that "justice was served" before the World Anti-Doping Agency had even reviewed the case and before the deadline for appeal had even expired. In addition, that statement has since been removed from the USADA's website, along with its previous statements and releases on no-fault contamination cases.

Meanwhile, since April, the US Congress, USADA and the US media have adopted a selective approach when it comes to the contamination cases of the Chinese swimmers when they attempt to mislead the international community and the general public by confusing right and wrong through fabrication and frame-up, the CHINADA statement said.

It added that the US has turned a blind eye to its long history of doping problems but is obsessed with "cross-border jurisdiction" and asserting sanctions against other countries. It seems that the accusation and attack on China and other countries is meant to deflect attention from the serious flaws in its own anti-doping efforts.

The CHINADA said the USADA should review the approaches and principles it has adopted in doping cases to ensure compliance with the goals of the global anti-doping system, and demonstrate integrity and consistency in their work. This is the right way to regain the trust of the international community, it said.