The USA is threatening to cut off funding to the World Anti-Doping Agency (WADA) unless it immediately enacts serious reforms, according to a report by the White House's Office of National Drug Control Policy (ONDCP).

The 19-page report seen by Reuters contains a series of recommendations to the US Congress that are highly critical of WADA, particularly its handling of the Russian doping scandal, and questions its use of taxpayers money.

The US is the largest single contributor to WADA, paying over $2.7m (€2.4m) to the 2020 budget of $37.4m (€33.2m), half of which comes from the International Olympic Committee (IOC).

"The United States Government has a duty to ensure that American taxpayer dollars are spent effectively for the purpose to which they are appropriated," the report said.

"American taxpayers should receive a tangible return on their investment in WADA in the form of clean sport, fair play, effective administration of the world anti-doping system and a proportionate voice in WADA decision-making."

The report details WADA's investigations into the Russian doping saga that began in 2015 when a WADA-commissioned report detailed state-sponsored doping in Russian athletics.

Russia is currently appealing a four-year ban from competing under its flag at major international sporting events, including the Olympics.

The suspension was imposed last December after WADA found that Moscow had provided it with doctored laboratory data.

"ONDCP hopes that WADA’s new leadership will implement necessary reforms to repair the damage done to WADA’s reputation and credibility in the wake of the Russian doping scandal," read the ONDCP report.

"However, the US Government will not rely merely on hope but will continue to insist upon structural reform of WADA and closely scrutinise."

Tygart, one of WADA's fiercest critics, labelled the report another "wake-up call".

"It is a damning report," Tygart said. "They (WADA) have got to change the way they are doing business or they are going to start losing funding."

WADA immediately condemned the ONDCP report, saying it was deeply flawed.

"It is very unfortunate that the report was written without due regard for the facts or context and with the clear intention to discredit WADA," WADA said in an email to Reuters.

The exchange is the latest salvo in a battle over control of the global anti-doping effort.

The Rodchenkov Anti-Doping Act, named after the whistleblower Grigory Rodchenkov who helped expose Russia's state-sponsored doping, is currently moving through the U.S. House and Senate.

If the bill is passed it would give the U.S. Department of Justice the ability to go after and prosecute those defrauding sport through doping in much the same manner FIFA officials were punished for corruption in soccer.

Tygart is unhappy that Russian officials, who orchestrated state-sponsored doping, have not only been allowed to escape punishment but in some cases have been rewarded.

The USADA chief pointed to the recent investigation into the International Weightlifting Federation whose former president Tamas Ajan was found to have covered up dozens of doping cases.

"Russia is the prime example and we have another one that just hit us.... which is the weightlifting federation," Tygart said.

"Its president not only misappropriated $10.5 million but also covered up over 40 doping cases that robbed clean athletes around the world.

"And what happens when he gets caught? He simply retires. He's probably on some beach sipping cocktails right now."