NAIROBI, Kenya (AP) — Kenya's new anti-doping agency said it had launched an investigation Saturday following a report by The Associated Press where two athletes who failed drug tests at last year's world championships alleged a senior official asked them for bribes in exchange for more lenient punishments.

The Anti-Doping Agency of Kenya (ADAK) promised a "comprehensive investigation" and said it had set up a committee to immediately investigate the claims. The body asked people with information on this case, or any others, to come forward.

In an interview with the AP, runners Joy Sakari and Francisca Koki Manunga alleged the chief executive of Kenya's track and field federation asked them for $24,000 each to reduce their suspensions after they failed doping tests at the worlds in Beijing. Sakari and Manunga didn't pay and are serving four-year bans for testing positive for the diuretic furosemide.

Athletics Kenya (AK) chief executive Isaac Mwangi has strongly denied the allegations, dismissing them as "just a joke."

The ethics commission of the IAAF, the international track and field body, is already investigating alleged extortion and doping cover-ups in Kenya involving other top officials. Three other senior officials, Athletics Kenya President Isaiah Kiplagat, vice president David Okeyo, and former treasurer Joseph Kinyua, were suspended in November pending the investigation.

They are accused of "subversion of the anti-doping control process in Kenya" among other allegations of wrongdoing.

The Kenyan lawyer leading the investigation for the IAAF said as many as six banned athletes have privately claimed to the IAAF commission that AK officials sought to extort bribes from them for lesser sanctions.

The IAAF has passed on the allegations made by Sakari and Manunga to its ethics commission, it said.

The Anti-Doping Agency of Kenya has itself been under scrutiny after long delays in starting work. The World Anti-Doping Agency announced Friday that it was putting Kenya on notice that it could be declared in breach of the global anti-doping code for failing to properly set up ADAK and finalize new anti-doping legislation.

ADAK also used Saturday's statement to say it was fully operational.

"ADAK wishes to take this opportunity to advise all national sports federations and all their affiliates including the athletes that we are now fully operational and that the sole mandate to handle all matters of anti-doping lies with the agency."

Kenya, a hotbed of distance running champions, is in the midst of a doping crisis with around 40 athletes failing drug tests since 2012.