Mohamed Morsi, the Egyptian president, has sacked several high-ranking officials including the country's intelligence chief and the governor of North Sinai.
"Obviously Israel was not involved in [the Sinai assault]. The Israeli intelligence gave warning both to the Egyptian government, and to Israeli travelers in Sinai who were told a few days earlier to vacate immediately. So if you give a warning you are not going to carry out the attack."
- Menachem Hofnung, a political science professor at the Hebrew University
The decision came after 16 Egyptian soldiers were killed in an attack in the Sinai near an Israeli border checkpoint.
Both Egypt and Israel blamed 'militants' from the Gaza Strip and the Sinai for the attack.
The claim could hurt ties between Hamas and Morsi, and has raised concerns over whether Egypt can secure the Sinai region.
Egypt closed the Gaza border crossing indefinitely after Sunday's attack, a move Hamas says amounts to a collective punishment.
Hesham Kandil, the Egyptian prime minister, announced on Wednesday that the army has started what it calls Operation Eagle, and that the Supreme Council of Armed Forces will issue a statement on the progress.
"We have to hear from the [Egyptian] presidency and from the Egyptian security to tell the truth to the people, to stop all kinds of rumours and all kinds of lies against the people in Gaza or against people in Egypt."
- Ghazi Hamad, Hamas' deputy foreign minister
While Egypt's hands are tied by the peace treaty with Israel when it comes to securing the Sinai through military reinforcements, the resulting lawlessness is increasingly worrying Israel.
Zvi Mazel, a former Israeli ambassador to Egypt, says: "If terrorism continues from Sinai to Gaza or from Sinai directly to Israel or from Sinai-Gaza-Israel, at a certain time at a certain point Israel will be forced to act, even to penetrate into Sinai, and it may change everything."
Inside Story asks: Can Egyptians secure the Sinai? And who stands to benefit from Sunday's attack?
Joining presenter Ghida Fakhry for the discussion are guests: Menachem Hofnung, a professor of political science at the Hebrew University; Sameh Fawzi, a political analyst; and Ghazi Hamad, Hamas' deputy foreign minister.
"[Egyptians] lack actual information until now. We don't have accurate and decisive information about what happened in Sinai. Most of the debates from different factions in Egypt are coloured by internal politics."
Sameh Fawzi, a political analyst
EGYPT-ISRAEL PEACE TREATY:
- These are allowed under the terms of the 1979 Camp David peace treaty between Egypt and Israel:
- Zone A is marked in the west by the Suez Cana, where an Egyptian infantry division with military installations and field fortifications are based.
- Zone B is in the middle, where four battalions are with up to 4,000 troops.
- Zone C in the east is the closest to Israel, where UN forces and lightly-armed Egyptian police are stationed.
- Egypt deployed an additional 1,500 troops to Zones B and C last year.