Five Jamaican athletes who are members of the team for next month's world championships have tested positive for a banned substance.
A Jamaican doping official speaking on condition of anonymity told Reuters that five athletes tested positive for a minor substance in testing during the national athletics championship in Kingston last month.
The source says none of the athletes were 'stars' at the Beijing Olympic Games last year.
However, the official said that two of the athletes are members of the newly formed Racers Track Club of which double Olympic champion and triple world record sprinter Usain Bolt is a member.
Bolt's coach Glen Mills also works at the club.