U.S. Olympic athletes sent a letter to leaders of the International Olympic Committee and World Anti-Doping Agency this week, urging them to expand the investigation into Russian doping to sports beyond track and field.

The letter came in response to the two-part report detailing doping inside Russia's track team, the sport's international governing body (IAAF) and allegations the government participated in the fraud.

The letter, sent Monday to IOC President Thomas Bach and WADA President Craig Reedie and obtained by The Associated Press, said that while other sports federations might do their own inquiries, WADA and the IOC should take the lead to make sure all Russian sports are investigated.

"With evidence of state-supported doping across the whole of sport in Russia, with a corrupt and ineffective ... testing system, and with athletes and insiders coming forward at great personal risk, now is exactly the time to investigate thoroughly," the letter said. "The clean sport movement is at a crossroads. The athletes of the world are watching and waiting."

The letter was signed by Sarah Konrad, an Olympic biathlete and cross-country skier who is chair of the U.S. Olympic Committee athletes' advisory council. The council, which represents 47 Olympic and 10 Paralympic sports, ratified the letter last weekend.

"I think it's pretty clear from the independent commission report that the corruption was countrywide," and it didn't just involve one sport, Konrad said.

The IOC did not immediately respond to requests for comment.

A WADA spokesman referred to Reedie's response letter to Konrad, also obtained by AP.

In the letter, Reedie spelled out the actions WADA took in the aftermath of the report, including declaring both Russia's track team and its anti-doping agency out of compliance. The track team is in a race to regain compliance before this year's Olympics. Reedie wrote that the suspension of the anti-doping agency has sparked reforms within the agency and given WADA a chance to examine the anti-doping corruption beyond track and field.

"Any evidence implicating other sports brought forward to me as a result of the meetings that WADA experts are holding with Russian representatives will allow me to make a considered decision on whether or not to initiate further investigations," Reedie wrote.

In his reports, Dick Pound, who led the WADA independent commission into the Russian doping, made mention of violations that could spread into sports outside track. But he made no recommendations on those because he was tasked to specifically look at athletics.

When first pressed to expand the probe, Reedie said it was something the agency needed to consider, but also had to find ways to pay for. WADA operates on an annual budget of about $26 million US, half of which is provided by the IOC.

Konrad said it's important for athletes outside the United States to also press WADA for an expansion of the inquiry beyond track. She also said she's well aware Russia isn't the only country with drug cheats.

"This is an opportunity to come down harder on this issue," Konrad said. "Sometimes, it feels like we're bashing our heads against a brick wall. But sometimes, if you bash long enough, a brick will fall out."