International Olympic Committee president Jacques Rogge on Saturday said the spate of recent positive doping cases was the result of aggressive testing of athletes ahead of the Beijing Games.
"This is the result of a deliberate strategy and policy. The IOC has asked the international federations... to do the maximum of doping tests before even the Olympic village has opened," he told reporters.
Rogge said the aggressive stance meant between 15 and 17 drug cheats had been uncovered ahead of the Games.
"These are 17 cheats that will not falsify the competition," he said.
Athletes from countries including Romania and Russia have been linked to drug scandals over the past few weeks.
The Beijing Olympics will see the biggest anti-doping effort in history, organisers have said, with testers promising developments in tracing substances such as human growth hormone, which are undetectable with standard testing methods, alongside the more commonly used steroids and the blood-booster EPO.