(CNN) — An alleged doping case involving 23 Chinese swimmers took a diplomatic twist on Wednesday after US lawmakers called on the US Department of Justice and the International Olympic Committee to launch inquiries into the controversy.

The Chinese swimmers tested positive for trimetazidine, a banned performance-enhancing substance, several months before the Tokyo Olympics – a tournament at which they were allowed to compete in, and went on to win medals at, according to a report from the New York Times released in coordination with German public broadcaster ARD.

“This scandal raises serious legal, ethical, and competitive concerns and may constitute a broader state-sponsored strategy by the People’s Republic of China (PRC) to unfairly compete at the Olympic Games in ways Russia has previously done,” said US Reps. Raja Krishnamoorthi and John Moolenaar, who are the two leading members of the House Select Committee on the Strategic Competition Between the United States and the Chinese Communist Party.

In a statement released Wednesday, the lawmakers called for an assessment as to whether the alleged doping was “state-sponsored,” adding that could warrant further diplomatic measures by the United States and the international community.

“Furthermore, with less than 100 days until the 2024 Olympic Games in Paris, understanding the full scope of the scandal is critical in ensuring our U.S. athletes are competing in a fair competition,” the statement added.

The World Anti-Doping Agency (WADA) last month dismissed allegations that the case was mishandled, describing them as “outrageous” and “completely false,” while the China Anti-Doping Agency (CHINADA) called media reporting about the situation “misleading.” It has previously said the positive results were the result of accidental contamination.

WADA has since commissioned an independent review into its handling of the case.

“WADA continues to stand by its handling of this contamination case. The truth is it followed every process and line of inquiry when reviewing this file and determined, based on compelling scientific evidence, that these were cases of contamination, not of doping,” a spokesman for WADA told CNN in an email.

“To this day, no evidence has been produced that suggests otherwise,” he added, noting that the organization awaits the findings of the independent enquiry.›

CNN has reached out to the Department of Justice and the IOC for comment.

According to the European Medicines Agency (EMA), trimetazidine “is a medicine used to prevent angina attacks, which are sudden pains to the chest, jaw and back brought on by physical effort, due to reduced blood flow to the heart.”

It has an effect on metabolism – where the body breaks down substances in order to convert them into energy. It increases the rate at which glucose is broken down, allowing it to be used to protect against myocardial ischaemia – reduced blood supply to the heart muscle – according to the EMA.

The reports have sparked concern among athletes and governing bodies.

The Canadian Olympic Committee called the media reports “concerning” and “not previously known to us,” while Sarah Hirshland, CEO of the US Olympic and Paralympic Committee, said that the organization was “deeply disheartened” about allegations which challenge “the very foundation of what fair competition stands for.”

In a press conference last month, WADA president Witold Banka said that the agency “followed all due processes and diligently investigated every lead and line of enquiry in this matter” and found “no evidence of wrongdoing … and no credible way to disprove the contamination theory that was accepted by CHINADA.”

A statement from CHINADA cited by Xinhua said the swimmers tested positive for an “extremely low concentration” of trimetazidine at a national swimming event in 2021.

Trimetazidine has the potential to boost endurance and has been banned by WADA since 2014.

CHINADA ultimately decided that the athletes should not be held responsible for the results after its “immediate” investigation concluded that they were inadvertently exposed to the substance through contamination, Xinhua reported.

Correction: The headline and article have been updated to more accurately characterize the case involving the Chinese athletes.