The US Anti-Doping Agency (Usada) says it “fully supports” the US government’s decision to withhold a payment of $3.6m (£2.8m) to the World Anti-Doping Agency (Wada).
It comes amid an ongoing dispute over the handling of a doping scandal involving Chinese swimmers.
It emerged in April that 23 swimmers from the country were cleared to compete at the Tokyo Olympics in 2021, despite testing positive for a banned substance months earlier.
Usada chief executive Travis Tygart said defaulting on the payment was “the only right choice to protect athletes’ rights, accountability and fair competition”.
In a statement he added that Wada “left the US with no other option after failing to deliver on several very reasonable requests, such as an independent audit of [its] operations, to achieve the transparency and accountability needed”.
The global anti-doping agency responded by saying representatives from the US would now be ineligible to sit on its foundation board or executive committee.
In April, Wada said it was “not in a position to disprove” an assertion from the China Anti-Doping Agency that they had unintentionally ingested heart medication trimetazidine (TMZ), which can enhance performance.
That sparked an outcry from Western anti-doping agencies and athletes, with Usada suggesting a cover up, a claim Wada rejected as “completely false and defamatory”.
It said it had been caught in “the middle of geopolitical tensions” between the US and China. An independent investigation found Wada did not mishandle the case or show bias towards the Chinese swimmers.
However, US lawmakers then accused Wada of failing to investigate the allegations properly and introduced legislation giving the White House Office of National Drug Control Policy the power to cut funding.
The US has been Wada’s highest government funding partner since it was formed in 2000 and will host the next two biggest global sporting events – the 2026 men’s World Cup and the 2028 LA Olympics.
“Since the exposure of Wada’s failed handling of the 23 Chinese swimmers’ positive tests that gave China and its athletes special treatment under the rules, many stakeholders from around the world – including athletes, governments and National Anti-Doping Agencies – have sought answers, transparency and accountability from Wada leadership,” said Tygart.
“Because Wada failed to uniformly enforce the global rules in place to protect the integrity of competition and athletes’ rights to fairness, significant reform at Wada must occur to ensure this never happens again.”
In a statement, Wada confirmed that “it did not receive the agreed contribution to [its] 2024 budget from the government of the US by the deadline of 31 December 2024.”
It added that its overall budget for 2025 was $57.5m (£46.5m).