At least 30 people are reported to have been killed in an Egyptian army offensive in northern Sinai on Saturday.
Tanks, armoured vehicles and troops backed by helicopters attacked Islamic fighters near Sheikh Zuweid, close to the Palestinian Gaza Strip.
The operation was be the biggest of its kind in recent years in Sinai.
There was an unsuccessful attempt to assassinate Interior Minister Mohamed Ibrahim in Cairo on Thursday. Security officials say those behind the suicide bombing were linked to groups in the Sinai.
Hardline groups have expanded into a security vacuum that opened up in North Sinai after the downfall of veteran autocrat Hosni Mubarak in 2011.
Attacks have escalated since 3 July, when the Army deposed president Mohamed Mursi Assaults on security forces and other targets in the desert occur almost daily.