The insurgency has swelled since the army’s ousting of Islamist president Mohamed Morsi in July 2013.
Militants loyal to Isil have killed hundreds of Egyptian soldiers and policemen, mostly in North Sinai.
A government crackdown targeting Morsi’s Muslim Brotherhood movement since 2013 has left hundreds dead and thousands jailed.
Hundreds more, including Morsi himself, have been sentenced to death, often in mass trials. Many have appealed and won retrials, while seven have so far been executed by hanging.