LONDON -- Usain Bolt believes the recent doping scandals in sprinting have 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 worlds.
"Definitely, it's going to set us back a little bit," Bolt said Thursday in London before a Diamond League meet, his first competition in the city since his three gold medals at last year's Olympics. "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."
He'll run the 100 meters Friday and 4x100-meter relay Saturday at the meet in London's Olympic Stadium, which marks the one-year anniversary of the opening ceremony.
In his first public comments since news of the high-profile doping cases broke July 14, Bolt promised that he won't be the next sprint star to be embroiled in a scandal.
"I was made to inspire people and to run, and I was given the gift and that's what I do," the six-time Olympic champion said. "I am confident in myself and my team, the people I work with. And I know I am clean.
"So I'm just going to continue running, using my talent and just trying to improve the sport."
If the recent cases have cast doubt about Bolt's integrity, the 100- and 200-meter world-record holder asked skeptics to check his résumé.
"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  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 oxilofrine at Jamaica's national championships in June. Discus thrower Allison Randall and two other athletes also returned positive tests for banned substances at the same meet.
"It was surprising, definitely, what's going on," Bolt said. "I think there's a lot of details that's left to be discussed. So I'm just sitting and waiting to see the results and what's what because there's a lot of things that hasn't been said and done yet."
Bolt said he reached out through text message with Powell after the positive test was announced.
"I didn't want to bombard him with questions," Bolt said. "I told him, 'Sorry to hear what was going on.' And he said, 'Yes, it's kind of rough. It's hard.'
"And I just told him to stay strong and stay focused and hopefully everything will work out."
Powell was the last man to hold the 100-meter world record before Bolt broke it in 2008. He also helped the Jamaicans to the 4x100-meter relay gold medal at the 2008 Olympics.
In almost 20 minutes with reporters, Bolt avoided any direct criticism of his fellow athletes.
"In life, things happen, people make mistakes, mishaps happen," Bolt said in response to a question about doping sanctions.
Both Powell and Gay claim they failed drug tests because they trusted people they didn't know well.
Bolt doesn't doubt his inner circle and was astounded by the suggestion he could inadvertently be given a banned supplement and test positive.
"What? I am clean," Bolt shot back while insisting he takes only vitamins, not supplements. "You have to be careful as an athlete what you do and what you ingest, the food you eat and stuff like that.
"But I am not worried because ... I have a great team around me to make sure everything go smoothly."
Bolt was asked about the severity of doping sanctions, whether a two-year ban was too lenient.
"Drugs are harsh on the sport. I can say it's really bad," he said. "I don't make the rules, really. I can't determine how harsh the rules should be."
While Bolt was speaking Friday, another doping case emerged involving a Jamaican sportsman.
The Caribbean island's soccer federation said it was notified by FIFA that a player tested positive for a banned substance after a World Cup qualifying match against Honduras on June 11, which Jamaica lost 2-0. The player and the substance involved were not identified.
Sprinter Kim Collins, who is competing in the two-day meet, accepts that every athlete is now under scrutiny. He says the recent doping cases "leave a bad taste for all of us."
"Everyone is judged, and I will be judged running fast at my age," said the 37-year-old Collins, a former 100-meter world champion from St. Kitts and Nevis.