Usain Bolt has hit out at people who make claims about the use of performance-enhancing drugs in athletics, and has "lost all respect" for former Olympic champion Carl Lewis.
On the day Bolt created history by winning the 200 metres to complete the sprint double for the second Games in succession, Victor Conte - the convicted owner of the Bay Area Laboratory Co-operative (BALCO) that supplied drugs to the likes of Dwain Chambers and Marion Jones - had claimed it was easy for cheats to prosper at London 2012 and that 60% of athletes are using drugs.
And while Bolt reacted angrily to Conte's claims when they were put directly to him, it was unclear exactly what sparked the Jamaican's diatribe against Lewis.
Lewis has previously questioned the stringency of Jamaica's drug-testing programme, but such comments were initially made in September 2008 - shortly after Bolt won three gold medals and set three world records at the Beijing Olympics.
"It is really annoying when people on the sideline talk stupid stuff," Bolt said in the mixed zone when asked about Conte's claims. "I think a lot of these guys who sit and talk, especially Lewis, no-one really remembers who he is, so he is just looking for attention. That is my opinion.
"It is really annoying to know that people are trying to taint the sport. The sport has been going forward. For someone to say that without any proof is really annoying. We work hard. We push ourselves to the limits."
Later, speaking at the official press conference for 200m medallists, Bolt added: "I am going to say something controversial right now; Carl Lewis, I have no respect for him. The things he says about the track athletes is really downgrading, for another athlete to be saying something like that about other athletes.
"I think he's just looking for attention really because nobody really talks much about him so he's just looking for attention. So that was really sad for me when I heard the other day what he was saying.
"For me it was upsetting. I have lost all respect for him. It was all about drugs, talking about drugs, a lot of drug stuff. For an athlete out of the sport to be saying that is really upsetting for me. That was really upsetting for him just to jump up and say something like that. As far as I'm concerned he's looking for attention - that's all."
Asked separately if he could assure people that Jamaican athletes were drug-free, Bolt added: "Without a doubt. We train hard, especially my team-mates. We see each other work every day.
"We work hard, we get injuries, we have to take ice baths, we lay on the track, so I see the work we put in to be the best that we are. When people doubt us it's really hard, but we're trying our best to show the world that we are running clean."