ASOIF's statement is the latest in a series of criticisms directed at the US over the case of 23 Chinese swimmers who were cleared to compete at the 2021 Tokyo Olympics despite testing positive for a banned substance.

An interim report by retired Swiss prosecutor Eric Cottier on Tuesday gave WADA a clean bill of health on the matter. Cottier stated that WADA had not mishandled the case, but this did not appease Travis Tygart, head of the US Anti-Doping Agency (USADA), a vocal critic.

On Thursday, WADA received the full support of the International Olympic Committee. On Friday, ASOIF openly expressed its dissatisfaction with USADA and the American justice system.

Brent Nowicki, the chief executive of World Aquatics, has been summoned to testify as part of the US criminal investigation into the affair. This investigation was initiated by the courts and the FBI under the Rodchenkov Anti-Doping Act at the request of a House of Representatives committee.

"The US criminal investigation into an anti-doping case on foreign soil and the recent position of the US Anti-Doping Agency threaten to undermine the role and independence of WADA and, by extension, confidence in the global anti-doping system and the autonomy of sports rules and regulations," said the ASOIF statement.

ASOIF also raised concerns about the safety of athletes and sports officials travelling to the US, which is "one of the largest sports markets in the world" and will host the 2028 Olympic Games in Los Angeles. They suggested that the uncertainties created by the US investigation could have significant consequences for the United States.

"The US extraterritorial investigation raises doubts about the personal security of athletes, sports officials and representatives of international sports organisations and the confidence with which they can travel to the US for international sports competitions and commitments," ASOIF said. "The investigation may lead International Federations (IFs) to consider the risks of awarding future international events to the US."

ASOIF has called for urgent clarification from the US Olympic and Paralympic Committee and the Los Angeles 2028 Organising Committee regarding WADA's position as an institution and respect for the fundamental principles of the World Anti-Doping Code.

The crisis began in April when the New York Times and German broadcaster ARD reported that the swimmers had tested positive for trimetazidine (TMZ),a banned heart drug that can enhance performance, at a domestic competition in late 2020 and early 2021. The Chinese anti-doping authorities determined that the swimmers had unknowingly ingested the substance from contaminated foodat their hotel and that no action was warranted against them.

WADA accepted this argument and did not sanction the swimmers. Some of them went on to compete at the 2021 Tokyo Olympics, with Zhang Yufei winning two gold medals and Wang Shun also becoming an Olympic champion. Eleven of the swimmers have been selected for the Paris Olympics, which begin in two weeks' time.

The case caused a global uproar, with US anti-doping authorities accusing WADA of a cover-up. As a result, WADA set up an independent investigation headed by Cottier. "There is nothing in the file - which is complete - to suggest that WADA showed favouritism or deference or in any way favoured the 23 swimmers who tested positive for TMZ," Cottier said in his report.