11.   All three athletes purportedly tested positive for banned performance-enhancing drugs, including testosterone, during the Olympic trials in Atlanta last June.

12.   At least one athlete tested positive, they added, but they refused to give any details.

13.   British athletics officials announced on Monday that a track athlete had tested positive for a banned substance but his or her identity would not yet be revealed.

14.   British athletics officials announced on Monday that a track athlete had tested positive for a banned substance.

15.   Drug testing was introduced for the first time, and six athletes tested positive.

16.   Earlier in the games, six athletes tested positive, including an Egyptian, an Algerian and a Kuwaiti.

17.   Eight other U.S. athletes tested positive for restricted asthma drugs, which they had permission to use.

18.   Earlier, six athletes had tested positive, including an Egyptian, an Algerian and a Kuwaiti.

19.   Five athletes tested positive for drugs during the last World Championships, in Athens, Greece, two years ago, including two who were stripped of their medals.

20.   Four athletes tested positive for banned drugs, including two who took anabolic steroids to enhance their performance.