Nine track and field athletes have been suspended for doping offences ahead of the London Olympics.
Among them are three who were caught in re-tests of samples from last year's world championships.
The sport's governing body said six were caught in biological passport tests, which measure changes in an athlete's blood profile.
The others were caught in retroactive testing from the championships in Daegu, South Korea.
Eight of the athletes have received two-year suspensions and one drew a four-year ban.
The IAAF characterised the cases as "sophisticated doping", including one involving human growth hormone and two tied to synthetic testosterone.
IAAF president Lamine Diack says the announcement shows that track authorities will "do everything in our power to eradicate cheating".