At least 26 Egyptian soldiers were killed or wounded on Friday in attacks on several checkpoints in Sinai that included car bombings, according to a statement released by the military.
The military added that in retaliation, it had killed 40 assailants in North Sinai, where Daesh is leading a deadly insurgency.
An Egyptian security sources said at least 23 soldiers were killed and around 26 more injured by the two deadly car bombs that ripped through army checkpoints in northern Sinai on Friday.
The two cars exploded on a road outside the border city of Rafah. No group has claimed responsibility for the attacks.
They said the attack happened when two deadly car bombs ripped through army checkpoints in the southern Rafah village of el-Barth. It was followed immediately by heavy gunfire from dozens of masked militants on foot.
The dead included a high-ranking special forces officer, Colonel Ahmed el-Mansi, and at least 20 others were wounded in the attack.
Sirens of ambulances were heard from a distance as they rushed to the site of the attack.
The officials spoke on condition of anonymity because they weren't authorised to speak to the media.
Army spokesman Tamer el-Rifai declined to comment immediately.
No group claimed immediate responsibility for the attack. However, Egypt in recent years has been battling a stepped-up insurgency in northern Sinai, mainly by militants from a Daesh-affiliated group.
Over the past months, Daesh has focused its attacks on Egypt's Christian minority and carried out at least four deadly attacks that killed dozens, prompting President Abdel Fattah el Sissi to declare a state of emergency in the country.
The Sinai branch of the Daesh group appears to be the most resilient outside Syria and Iraq, where the so-called caliphate is witnessing its demise in those countries.