KINGSTON, Jamaica - Jamaica's triple Olympic and world champion Usain Bolt's sprint training partners Yohan Blake and Marvin Anderson were among four Jamaican runners who have admitted taking banned substances.

"The athletes have admitted they took a banned substance," Jamaican Anti-Doping Appeals Tribunal chairman Ransford Langrin said in a statement.

"We have to decide now what is the sanction we apply - and the minimum sanction is a reprimand or up to a two year ban."

Samples taken at the Jamaican Championships from June 26-28, the qualifying meet for last month's World Championships in Berlin, were positive for the four as well as Commonwealth Games 100m champion Sheri-Ann Brooks.

All were cleared at first because the substance found was not on the WADA banned list or of similar composition, but the Jamaica Anti-Doping Commission appealed the finding, saying it had similar chemical structureto tuaminoheptane.

The Jamaica Anti-Doping Appeals Tribunal upheld tossing out the positive test for Brooks because her "B" sample was tested without her knowledge.