LONDON – Usain Bolt believes the recent doping scandals in sprinting hurt the sport and insists he's running clean.

The world's fastest man stopped short of condemning fellow Jamaican sprinters Asafa Powell and Sherone Simpson or American rival Tyson Gay, whose failed doping tests have left the sport in turmoil ahead of the world championships.

"Definitely, it's going to set us back a little bit," Bolt said in London, where on Friday he won the 100 meters in a Diamond League meet. "But as a person, I can't focus on this."

Bolt said it won't affect his preparations for the upcoming world championships in Moscow.

"I still have world championships, everyone is stepping up their game, so I have to really focus on that," he said. "I am just trying to work hard, run fast and hopefully help people to forget what has happened and just move on."

If the recent cases have cast doubt about Bolt's own integrity, the 100- and 200-meter world record-holder asked skeptics to check his record.

"If you were following me since 2002, you would know that I have been doing phenomenal things since I was 15," the 26-year-old Bolt said. "I was the youngest person to win the world juniors at 15. I ran the world junior [200] record 19.93 at 17. ... I have broken every record there is to break, in every event I have ever done."

Powell and Simpson tested positive for the stimulant oxilofrone at Jamaica's national championships in June. Discus thrower Allison Randall and two other athletes also returned positives for banned substances at the same meet. Gay, it was revealed Friday, has failed at least two drug tests in the past year.