Egyptian authorities confiscated some 1.7 million documents reportedly proving Jewish ownership of land and assets in Cairo. The documents were reportedly about to be shipped out of the country to Israel, in what the Egyptian daily Al-Ahram is calling “the most dangerous case of security breach in history.”

The documents were found in 13 large cases, ready to be transported to Jordan and from there to Israel, Egyptian media reported Sunday.

Elaph, a Saudi-owned news site, reported that Egyptian police received notice that the packages were being held at a shipping company in the Nasser City district of Cairo. Upon arriving at the scene, police found over 1.7 million documents dating back to the 19th century, dealing with Jewish ownership of assets in Cairo. The documents, according to the security source speaking to the Saudi site, weighed over two tons.

According to Elaph, Egyptian President Mohammed Morsi is personally following the case

Preliminary investigations have revealed that the documents were supposed to be used in an Israeli lawsuit involving Jewish property lost in Egypt’s 1952 revolution, the site reported. According to Elaph, Egyptian President Mohammed Morsi is personally following the case, which it said affects Egypt’s national security.

The documents were reportedly stolen on December 16, 2011, from a Cairo research institution, the Institut d’Égypte, during public riots that erupted following president Hosni Mubarak’s ouster.

According to Al-Ahram, an unnamed senior member of former Mubarak’s National Democratic Party (NDP) was involved in the efforts at smuggling the documents out of the country, in the service of a French-Jewish woman. Another man implicated by Al-Ahram is a Jewish Lebanese businessman named Robert Khalil Sarsaq, who also holds other nationalities. Elaph’s source claimed that the two are suspected of having ties with the Mossad.

The source noted that some of the documents, containing Jewish ownership deeds for banks, companies and real estate, date back to 1863. The documents are now being held by Egypt’s general prosecution.

Israel’s Deputy Foreign Minister Danny Ayalon recently launched a campaign encouraging Jewish refugees from Arab states to come forward and present testimonials of the circumstances that led them to flee their countries of origin.

Egypt’s Jewish community numbered some 75,000 before the founding of Israel in 1948. By 1957, only several thousand Jews were left in the country; most of the others had fled under Arab pressure, according to contemporary accounts.

In 2009, the government of Prime Minister Benjamin Netanyahu established a national advisory council to examine Jewish claims of lost property in Arab countries, but the council was moved from the Justice Ministry to the Pensioner Affairs Ministry, and did little to register property claims.