World Aquatics confirmed last week that its executive director Brent Nowicki has been subpoenaed by the U.S. government to testify in an investigation into how the Chinese swimmers escaped punishment after testing positive and weeks later were allowed to compete in the Tokyo Olympics.

A U.S. House of Representatives committee in May called on the Department of Justice (DOJ) to launch inquiries ahead of this year's Paris Olympics to ensure American athletes would be competing on a level playing field.

The results of an independent investigation into the Chinese matter by Swiss prosecutor Eric Cottier released on Tuesday found the World Anti-Doping Agency (WADA) had not mishandled the case.

"The Association of Summer Olympic International Federations is greatly concerned that the leadership of one of its member International Federations (World Aquatics) has been ordered to testify as a witness in a United States (U.S.) federal investigation," said ASOIF.

The U.S. investigation has chilled relations between the 2028 Olympic host country and a chunk of the international sporting community with some federations expressing concern about sending officials to the United States over fears they could be arrested.

Images of members of soccer's world governing body FIFA being arrested on U.S. corruption charges as they exited a Zurich hotel in 2015 remain fresh and not a scene the International Olympic Committee (IOC) or member federations would like to see repeated.

"The U.S. extraterritorial investigation raises doubts about the personal safety of athletes, sport officials and representatives of international sport organisations and the confidence with which they may travel to the U.S. for international sporting competitions and commitments," said ASOIF in a statement.

"The investigation may lead IFs (international federations) to consider the risks of allocating future international events to the U.S."

ASOIF said it wants clarification from the U.S. Olympic and Paralympic Committee (USOPC) and the 2028 Los Angeles Olympic Organising Committee regarding their position on WADA, which has come under intense criticism from United States Anti-Doping Agency (USADA) chief Travis Tygart.

Neither USADA, USOPC or the organisers of the 2028 Los Angeles Olympics or 2034 Salt Lake City Winter Games responded to a Reuters request for comment.

Any investigation would fall under the Rodchenkov Act legislation passed in 2020 that extends U.S. law enforcement jurisdiction to any international sporting competitions that involve American athletes or have financial connections to the United States.

Named after Grigory Rodchenkov, a former Russian anti-doping laboratory head who turned whistleblower and helped expose Russia's state-sponsored doping, the act criminalises doping schemes intended to influence sports events and allows U.S. prosecutors to seek prison terms of up to 10 years and fines of up to $1 million.

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