The world doping body WADA demanded detailed information on a host of Greece's top Olympic competitors on Monday, according to a Greek team official.
Greece's chef de mission Yiannis Papadoyanakis said WADA required names and whereabouts of all track and field athletes, swimmers, weightlifters and triathletes.
"We do not know if other teams have been required to give the same details," he said.
Officials earlier revealed that two unnamed Greek baseball players had tested positive for banned substances. Results from a second test were expected on Monday afternoon.
Papadoyanakis said top Greek track athletes Costas Kenteris and Ekaterini Thanou were not in Greece and would not return in time for the August 13 opening ceremony.
"We will fully cooperate with WADA... The Greek team will crack down on doping wherever we find it," said Papadoyanakis.