DOHA, Qatar -- Track and field's governing body will immediately apply its testosterone regulations to the 1,500 meters, president Sebastian Coe said Thursday, ignoring advice from the Court of Arbitration for Sport.

The CAS said Wednesday that there was not enough evidence to show Caster Semenya and other female athletes with naturally high testosterone levels had a significant advantage in that event.

The CAS upheld the IAAF's rules limiting testosterone for athletes competing in some events, including Semenya's favored 800 meters, in its landmark ruling.

But in a caveat to the decision, the Switzerland-based court specifically said there was "a paucity of evidence" to apply the rules to the 1,500-meter and one-mile races. The CAS asked the IAAF to delay the rules in those events until it provides more evidence.

Asked a day later at a news conference in Doha, Qatar, if the IAAF would heed that advice from sport's highest court, Coe simply said: "No."

Despite saying the IAAF would ignore the CAS' advice on the 1,500 rules, Coe said he was "really grateful" to the court for its overall decision.

Having answered two questions from reporters on the CAS decision, Coe refused to speak any more on the issue.

Coe's response to the 1,500-meter question fuels Semenya's argument that the IAAF is deliberately sidelining the South African star because of her success. The two-time Olympic and three-time world champion in the 800 recently put more focus on the 1,500 as an alternative. She won a bronze medal in the 1,500 at the 2017 world championships.

Semenya, 28, gave her strongest criticism yet of the IAAF when she said in a statement in the wake of the CAS decision: "I know that the IAAF's regulations have always targeted me specifically. For a decade the IAAF has tried to slow me down, but this has actually made me stronger."

Semenya now has the option of submitting to the IAAF rules and medically reducing her testosterone to be able to compete in the 800 or 1,500 at major meets. Or she could run longer distances and not have to medicate. She hasn't indicated what she will do.

Semenya and another athlete who has publicly announced she has a testosterone condition, Francine Niyonsaba of Burundi, will both run in the 800 at the Diamond League meet in Doha on Friday.

It will be the last top-class women's 800 before the testosterone regulations go into effect next week.