The International Olympic Committee has filed a lawsuit against a Greek track coach after two of his athletes were expelled from the Beijing Games for doping.

Alexandros Lykourezos, a lawyer representing the IOC, said the action was taken to seek potential prosecution in Greece of coach George Panagiotopoulos.

The move follows the expulsion from the Beijing Games of Fani Halkia, the 2004 Olympic women's 400-metre hurdles champion, and sprinter Tassos Gousis. Both athletes tested positive for the steroid methyltrienolone.

"We have taken this (legal action) against Mr Panagiotopoulos - coach of Ms Halkia - and all others considered responsible," Lykourezos said. "At the same time, the IOC declared its willingness to participate as a civil claimant.

"The IOC, as specified by its charter, aims to organise drug-free games as well as to foster, promote and protect the principles of the Olympic Spirit."

The two runners and Panagiotopoulos have denied any wrongdoing - suggesting the failed tests may have resulted from contaminated diet supplements.

Lykourezos said the doping violations had "damaged the reputation of the Olympic movement."

He said IOC medical director Patrick Schamasch was willing to provide testimony to Greek judicial investigators.

Earlier this month, a senior Greek prosecutor launched a preliminary investigation to determine whether the Greek athletes and their coach broke any Greek laws.

They are due to give evidence next week.

Investigators have already interviewed Isidoros Kouvelos, head of the Greek Olympic team in Beijing, and Vassilis Sevastis, head of the Greek Amateur Athletic Association.