Egyptian antiquities supremo Zahi Hawass opened an international conference on recovering ancient artefacts from abroad, saying countries must unite to recover their stolen heritage.
"We need to cooperate, we need a unification between our countries," Mr Hawass told antiquities officials, deputy culture ministers and museum directors from 21 countries at the two-day Cairo meeting.
"Every country is fighting alone, every country suffered alone, especially Egypt," Mr Hawass told the delegates from countries that have seen their national heritage looted over the centuries.
"We will battle together," he said, adding that "maybe we will not succeed in a lifetime (but) we have to open the subject."
Mr Hawass, who heads Egypt's Supreme Council of Antiquities, urged delegates to draw up lists of artefacts missing from their countries and displayed in museums abroad.
"This conference shows the importance many countries place in joining forces," said Elena Korka, who is in charge of protecting Greece's cultural heritage.
Athens has been locked in a 30-year antiquities "war" with London to retrieve the Elgin Marbles from the British Museum, and Egypt has been fighting for the Rosetta stone from Britain and a bust of Nefertiti from Germany. A major aim of the conference is to call on the United Nations cultural body Unesco to amend a 1970 convention banning the export or ownership of stolen antiquities acquired after that date.
The convention prohibits the illicit import, export and sale of cultural property, but stipulates there will be no "retroactive" measure for artefacts acquired before the convention was signed. Over the years, Mr Hawass has made the return of looted Egyptian artefacts the hallmark of his tenure and won many battles to bring home Pharaonic items and other ancient relics.
In March, Egypt said it retrieved from Britain some 25,000 ancient artefacts, including a stone axe dating back 200,000 years and pottery from the seventh millennium BC.
But Mr Hawass is still eyeing the Rosetta stone held by the British Museum for more than 200 years and the 3,400-year-old bust of Queen Nefertiti on display at the Neues Museum in Berlin.
The iconic Rosetta stone, which dates back to 196 BC, was found by French forces in Egypt in 1799 and given to the British under a treaty two years later.
Its discovery led to a breakthrough in deciphering hieroglyphics, as it gives the same text in the ancient Egyptian script, plus the demotic Egyptian that was the common language and Greek, which was the language of officialdom.
As for the Nefertiti bust, Germany has repeatedly rebuffed Egyptian claims to the rightful ownership of it and says the priceless sculpture was acquired legally nearly a century ago. Egypt says it was spirited out of the country.
Last year Egypt broke off relations with the Louvre Museum until France finally returns stolen steles chipped off a wall painting in the ancient tomb in Luxor's Valley of the Kings.