Former world 1,500m champion Abeba Aregawi has been provisionally banned following confirmation that she has tested positive for a banned substance.
The Ethiopia-born Swede, who won the 2013 World Championships in Moscow and the Sopot World Indoor Championships 12 months later, has failed an out-of-competition test.
"Following notification of the laboratory finding, the athlete has voluntarily withdrawn from competition until the investigations into the laboratory finding are completed," read a statement from the International Association of Athletics Federations.
"In the meantime, the athlete has requested the analysis of the B sample which will be conducted shortly.
"The IAAF and the Swedish Athletic Federation will not make any further comment until completion of the result management procedure."
Aregawi has been competing for the Scandinavian nation since 2012.