The lawyer of whistleblower Grigory Rodchenkov has branded FIFA as the latest of many international sports organisations to be "sweeping Russia's doping fraud under the carpet".
It was recently confirmed by FIFA that no anti-doping cases are being pursued against any players named in Russia's provisional squad for their home World Cup starting next month.
Investigations of Russian footballers not in the World Cup squad are "still ongoing", however, with further updates to be provided "in due course".
The world governing body's statement was issued two days after the airing of an ARD documentary in Germany in which Moscow Laboratory director turned whistleblower Rodchenkov, who is in witness protection in the United States, alleged that positive tests in Russian football were ordered to be ignored.
Football was among dozens of sports implicated in evidence of sample tampering at the Moscow Laboratory, which was disclosed in the World Anti-Doping Agency (WADA)-commissioned McLaren Report following evidence from Rodchenkov.
Rodchenkov’s lawyer Jim Walden has now released a damning statement on FIFA's investigation of Russian athletes and state-sponsored doping.
"I have come to expect that many international sports organisations, for various reasons, are declining to conduct meaningful investigations, and are desirous of sweeping Russia's doping fraud under the carpet," he said.
"FIFA is merely the latest.
"This situation will never improve, and clean athletes will never be protected, unless [the US] Congress passes a criminal statute to prosecute doping fraud at international competitions.
"I will continue to urge Congress to pass one."
FIFA claims to have assessed all information and evidence contained in the McLaren Report, with the support of scientific and legal experts.
This included Rodchenkov and Canadian lawyer Richard McLaren.
It also claims to have re-analysed "samples taken by FIFA and the Confederations that had been stored at WADA-accredited laboratories, of all players mentioned in the McLaren Reports and high-level players".
All supposedly returned negative results.
Samples "seized" by WADA from the Moscow Laboratory and stored at the Lausanne laboratory were re-analysed for prohibited substances and have also returned negative results.
FIFA claims to have subjected these samples to forensic analysis for scratches, marks and abnormal salt levels using "methodology recommended by WADA and used by the International Olympic Committee".
"None of the samples analysed showed marks that were typical of tampering and the urine did not show any suspect salt values," the body stated.
FIFA also claims to have analysed the Laboratory Information Management System data of the Moscow Laboratory obtained by WADA with the "support of scientific and legal experts".
Furthermore, it has performed "several unannounced targeted doping controls in the process of the investigations and the Russian squad has been one of the most tested teams prior to the FIFA World Cup".
FIFA's statement made no mention of Ruslan Kambolov, the defender who was dropped from the Russian World Cup squad with a supposed calf injury and who had been the subject of a FIFA investigation, or of probes against members of Russian youth teams.