The Egyptian authorities have seized documents which reportedly confirm Jewish ownership of property in Cairo.
The 1.7 million documents, weighing two tonnes, were confiscated as they were being shipped to Israel via Jordan.
The attempted delivery of the documents was called “the most dangerous case of security breach in history” by Egyptian media on Sunday.
Israeli authorities intended to use the documents and deeds in a legal suit to reclaim property that was confiscated from Cairo’s Jews during the 1952 revolution.
Levana Zamir, president of the association of Egyptian Jews in Israel, said: “Those 1.7 million documents belonging to the Jews of Egypt, are the best proof that we are now dispersed all over the world [and] left behind billions of our assets.
“All those 1.7 million documents, belonging to us, must be transferred to us.
“There are many Jews from Egypt who would like to recover their family possessions left behind by their fathers – but this is impossible today in Egypt."
Ms Zamir, 74, added that there are only two Jews remaining in Egypt – a woman in Cairo and a man in Alexandria. She was forced to leave Cairo in 1950 and now calls herself a “refugee living in Israel”.
Egyptian President Morsi has taken a personal interest in the case and is reportedly concerned that losing the documents could adversely affect national security. The documents were stolen from the Cairo research institute, the Institut d’Égypte, during last year’s public riots.
Danny Ayalon, the Israeli deputy foreign minister, recently launched a UN campaign on the rights of Jewish refugees from Arab nations.