Sprinters Shelly-Ann Fraser-Pryce and Carmelita Jeter have walked out of a news conference in protest at questions on the latest drug scandal to hit athletics.

Double Olympic 100m champion Fraser-Pryce of Jamaica and world champion Jeter of the United States were attending a media briefing to preview tonight's Diamond League meeting in Monaco.

News of Tyson Gay and Asafa Powell's failed drugs tests has cast a shadow over tonight's action, but Fraser-Pryce and Jeter had made clear prior to meeting the press that they would not discuss the issue - and duly walked out when the inevitable questions came.

Instead it fell to American sprinter Justin Gatlin to speak on the matter.

Gatlin won 100m Olympic gold in 2004 Olympic but in 2006 served a four-year ban after testing positive for a banned substance.

He has since been able to make a successful return to the sport and believes athletics can recover from this latest setback.

"I still believe in it," Gatlin told the press conference. "I'm still a fan of the sport. We just have to get past this. The young athletes have to go out there and shine."

On his own experiences, he added: "It was a rebirth for me to be able to come and be able to gain the respect of the community again.

"I think people accept me now."

"It was a rebirth for me to be able to come and be able to gain the respect of the community again" - Justin Gatlin

The spate of failed drugs tests has again shone a light on the dangers of athletes taking supplements, and Gatlin said: "I think this shows a lot of the young athletes that it doesn't have to be old stone-age steroids that are given to you in a syringe.

"It can be something from over the counter that's given to you. You just have to make sure that you're responsible for what's going into your body."

Gatlin was speaking on the same evening discus thrower Traves Smikle became the latest Jamaican athlete to reveal he had tested positive for a banned substance.

The 21-year-old, who represented Jamaica at the London Olympics last year, said he had been informed by the Jamaica Anti-Doping Commission (JADCO) that his A sample had returned a positive result after the Jamaican trials last month.

In a statement published by the Jamaica Observer, Smikle said: "As an athlete, I must take responsibility for whatever is found in my body; however, I wish to state that I did not knowingly or wilfully ingest any banned substance.

"I have requested analysis of the B sample and await notification of the time and date for this to be done.

"I am willing and stand ready to work with JADCO and the relevant authorities in any investigation to get this matter dealt with in the best way possible.

"Personally, I am very saddened and surprised by these findings, as I have never attempted to cheat and have always considered myself an ambassador for the sport and a strong supporter of drug testing."

Smikle follows Jamaican sprint stars Powell and Sherone Simpson in confirming their adverse findings, along with another discus thrower, Allison Randall.

All four athletes deny deliberately using a banned substance.