Former reporter Susan Yara took the Biophysical250 test after years of low-level but persistent digestive discomfort that was never accurately diagnosed, despite numerous tests for thyroid disorders and irritable bowel syndrome.

FORBES: An Uneasy Mark

Gatlin, the 2005 world 100m and 200m champion, gave a positive test for testosterone at the low-level Kansas Relays in April 2006.

BBC: Gatlin won the 100m title at the Athens Olympics in 2004

The BBC's Paul Welsh in the Macedonian capital, Skopje, says Western diplomats expect some low level violations of the ceasefire, and the real test will be whether any new large scale confrontations break out.

BBC: News Online