Kingston - Asafa Powell and Sherone Simpson are among five athletes who reportedly tested positive for banned performance-enhancing drugs at last month's Jamaican national championships.
Sources told Reuters earlier on Sunday that two of the athletes were sprinters while three competed in field events. They said one of the athletes was a junior.
Later on Sunday it was confirmed that two of the athletes involved were Olympic 4x100m relay silver medallist Simpson and former world 100m record holder Powell.
"I will confirm that a sample I gave at the National Trials in June earlier this year has returned 'adverse findings'," Powell said in a statement to Reuters.
"The substance oxilophrine (methylsynephrine) was found, which is considered by the authorities to be a banned stimulant," the 30-year-old sprinter added.
"I want to be clear in saying to my family, friends, and most of all my fans worldwide that I have never knowingly or wilfully taken any supplements or substances that break any rules. I am not now, nor have I ever been a cheat."
This follows Sunday’s earlier news of America's former world champion Tyson Gay announcing he had failed a dope test.
Powell, who has never won an individual global sprint title, held the 100m world record between 2005 and 2008 when his then-best of 9.74 seconds was broken by current record-holder and fellow Jamaican Usain Bolt.
"This result has left me completely devastated in many respects," Powell said. "Professionally, this finding fully negates any possibility of me being a part of Jamaica's contingent of athletes competing at (the) world championships in Moscow later this summer."
Powell, who was battling injuries earlier this year, failed to qualify for next month's Moscow world championships, finishing seventh in the 100.
He has since re-emerged as an elite sprinter, clocking 9.88 seconds earlier this month in Lausanne and raising speculation he could be added to Jamaica's 4x100m relay team.
"I accept the consequences that come with this finding - after all there is only one Asafa Powell," he said. "My fault here however is not cheating but instead not being more vigilant.
"I want to reiterate that in my entire career as an athlete I have never sought to enhance my performance with any substance. It is not a part of who I am or what I believe in."
Simpson, 28, finished equal second in the 100m at the 2008 Beijing Games and won a gold medal in the 4x100m relay four years earlier in Athens.
"This is a very difficult time for me," she said in a statement to Reuters. "I was notified on July 14, 2013 that my urine sample taken at the National Senior Championship, June 21, 2013 after the 100m finals returned a positive analytical finding for a stimulant, oxilofrine (methylsynephrine)."
Jamaican Anti-Doping Commission (JADCO) chairman Herb Elliott confirmed the body had received "reports of adverse analytical findings from "A" samples".
"The process of the result management has commenced in accordance with the JADCO Anti-doping rules," he told Reuters.
"We cannot disclose any further information until the athletes have responded to notification of the "A" sample."
Last month Jamaica's most successful female athlete Veronica Campbell-Brown tested positive for a diuretic, which can be used to mask the use of performance-enhancing drugs.
The twice Olympic 200m champion has been suspended by the Jamaican Athletics Administrative Association pending the outcome of a disciplinary panel hearing.