PARIS — A feud between the world’s leading sports anti-doping organizations just escalated again.

This time, U.S. officials face accusations they improperly allowed American athletes to compete in “elite level” events after tests showed they used performance-enhancing drugs. Deals were struck with at least three athletes if they agreed to serve as informants and cooperate in on-going doping investigations. Reuters first reported the practice.

The World Anti-Doping Agency (WADA) says the U.S. Anti-Doping Agency (USADA) ran a rogue operation that turned athletes into “undercover agents.”

“WADA did not sign off on this practice of permitting drug cheats to compete for years on the promise that they would try to obtain incriminating evidence against others,” the organization said in a statement.

According to WADA officials, when they learned of the practice by USADA in 2021, they ordered the Americans to “desist.”

This salvo from international anti-doping officials based in Montreal, Canada, comes after WADA itself faced growing criticism for its handling of positive drug tests involving 23 Chinese swimmers.

WADA kept the positive drug tests taken in 2021 and 2022 secret, allowing the Chinese athletes to keep competing, at the Tokyo Summer Olympics and again at the Paris Games this year.

In a statement, USADA CEO Travis Tygart said WADA is raising concerns over the secret use of American athletes in its investigations as a “desperate and dangerous” effort to smear critics.

According to Tygart, WADA was “aware of the athletes’ cooperation” in probes of sports doping and knew some athletes had been allowed to return to competition.

USADA said in its statement athletes who worked undercover while still competing “provided intelligence” to U.S. federal law enforcement and anti-doping investigators that eventually led to criminal charges.

“When USADA and other anti-doping organizations obtain information about misconduct and potential violations,” Tygart said, “it’s critical that we pursue the truth with all the resources at our disposal.”

According to both organizations, the practice of allowing proven sports cheaters to continue competing, in exchange for cooperation, is no longer in use.

This fight comes as USADA’s Tygart has emerged as a chief public antagonist of WADA, calling for major reforms to the world’s premier anti-doping organization. The U.S. Congress opened a probe and the FBI also launched a criminal investigation.

WADA and the International Olympic Committee have punched back, arguing that U.S. officials have overstepped their authority. The IOC threatened last month that Salt Lake City’s hosting of the 2034 Winter Games could be revoked if U.S. probes and criticism continue.

As this diplomatic fight between the world’s most powerful sports organizations grows more bitter, many American athletes say they no longer trust the system designed to preserve fair, drug-free competition.