Greece is prepared to wait for the outcome of talks between UNESCO and Britain over the return of the Elgin Marbles before launching legal action, says its culture minister and lawyers including George Clooney's new bride.
Amal Alamuddin Clooney, one of a trio of high-profile lawyers drafted in to advise the Greek government over the artefacts that were taken to London two centuries ago, said the "injustice has persisted for too long".
"The Greek government has a just cause and it's time for the British Museum to recognise that and return them to Greece," she told a press conference.
UNESCO, the UN's cultural and scientific body, this month asked Britain and Greece to accept it acting as a mediator in the long-running case.
London has six months to give its response to the proposal.
The Parthenon marbles owned by the Greeks are exhibited alongside plaster copies of those that remain in London.
Clooney said: "One of the most beautiful piece of art in the world is still not available to anyone to see and appreciate as a whole."
"Nobody can celebrate the marbles united in the place where they come from."
Geoffrey Robertson, a veteran lawyer with a track record of fighting highly publicised cases in Britain, said mediation could be "very helpful".
If that did not work, "the next step would be to go on a international court", he told the press conference.
"We're not planning that at this point..., but there are legal opportunities and we should be aware that there are international courts."
The involvement of the new wife of one of Hollywood's biggest stars has inevitably sparked a media circus.
The 36-year-old has been mobbed by photographers at every step of her visit to Athens, including when she met Greece's culture minister, Konstantinos Tasoulas, for discussions.
The sculptures were taken from the Parthenon by British diplomat Lord Elgin in 1803 and shipped to Britain.