Following a New York Times report last month detailing events that led to Chinese swimmers avoiding sanctions after testing positive for a banned substance weeks before the Tokyo Olympics, WADA has been fending off criticism and accusations of a cover-up.

But during an extraordinary virtual meeting of its Foundation Board on Friday, WADA blasted its most vocal critic, the United States Anti-Doping Agency (USADA) and the organisation's chief Travis Tygart as hypocrites.

Canadian Dick Pound, who established WADA in 1999, came to his organisation's defence, accusing Tygart of lies and distortions and suggesting USADA's claims were politically motivated.

"On behalf of WADA, I am deeply disappointed and disgusted by the deliberate, lies and distortions coming from USADA, including that WADA has swept doping cases in China under the rug," said Pound, a former IOC member.

"That accusation, bereft of any truth, has but a single purpose to deliberately damage the reputation of WADA.

"To claim that WADA has in some way inappropriately favoured China is completely false," Pound added.

"USADA is financed by the United States government, that government currently has a chilly relationship with China's government. Could there be a connection?"

WADA has stood firm against criticism, arguing that it followed rules and procedures laid out in the anti-doping code and had no evidence to challenge China's findings.

The swimmers avoided sanctions after an investigation by Chinese authorities ruled the positive tests were the result of being inadvertently exposed to the drug through contamination.

A report determined all the swimmers who tested positive were staying at the same hotel where traces of trimetazidine (TMZ), which is found in heart medication, were discovered in the kitchen.

INDEPENDENT REVIEW

WADA announced in April that it would launch an independent review of the matter led by Swiss prosecutor Eric Cottier.

"Trust comes from truth and transparency, not obfuscation and childish bluster." said Tygart, responding to WADA's comments.

"Unfortunately, we all know that when you are afraid of the facts, the classic response is to attack the messenger, distract from the real issues, and make it personal."

Tygart said the meeting today demonstrated that the global anti-doping system needed immediate reform.

"The world has legitimate questions about how WADA could turn a blind eye to 23 positive tests on the eve of the Tokyo Olympic Games, and today WADA reinforced those concerns by admitting they purposefully tried to keep this information from going public — the very definition of sweeping it under the carpet," he said.

WADA President Witold Banka said that when it comes to anti-doping, U.S. athletes are some of the least tested in the world and that USADA has used the contamination explanation to clear Americans of positive tests.

"There have been a number of environmental contamination cases in the past, in fact, some of the most elaborate and surprising contamination scenarios have come out of the U.S.," Banka said.

"Just to paint a picture of some inconsistent rule implementation in the U.S. 90% of American athletes, those in the professional leagues and college sport do not compete under the world anti-doping code."