Egypt's Chief of Military Intelligence Mohammed Farag El-Shahat said that the Egyptian army has killed nearly 500 militants in Sinai in military operations launched under the name "the martyr's right' since 2015.
Egypt's security forces have been battling a decade-long militant Islamist insurgency, which intensified since the ouster of Islamist president Mohamed Morsi on 3 July, 2013.
The insurgency has been mainly concentrated in North Sinai 's Rafah, Arish, and Shiekh Zuwied.
Militant attacks have left hundreds of police and army personnel dead.
El-Shahat statements came during the Egyptian Armed Forces 24th intellectual seminar titled "Counter-terrorism; a Nation's Will" that commenced on Thursday.
The military intelligence chief said that the banned Muslim Brotherhood organisation formed an alliance with the Islamic State militant group, which is based predominantly in North Sinai, a move aimed at putting the Brotherhood back in power.
El-Shahat cited as proof of this alliance a statement made in early July 2013 by Mohamed El-Beltagy, a leading Muslim Brotherhood figure who is now in jail on various criminal convictions, in which he said that terrorism in Sinai would stop at the moment ousted president Morsi returns back to power.
In December 2013, Egypt designated the Muslim Brotherhood a terrorist organisation, after the authorities blamed the group for a number of deadly attacks against security forces in the aftermath of the ouster of Morsi.
"Militants attempted to announce an Islamic state in North Sinai's Sheikh Zuweid city after they launched a major attack on 1 July 2015," El-Shahat stated.
El-Shahat said the army and police in North Sinai foiled this attempt, causing tangible loses among militants and terrorist groups.
On that day, the army said it killed more than 100 militants during its counter-attacks in Sheikh Zuweid and Rafah cities.
The army also said 17 army personnel including four officers and 13 others were injured during the fighting.
The Egyptian military intelligence chief also said that the state of instability in many countries in the region contributed to the rise of terrorist attacks in Egypt during this period.