Five Egyptian soldiers were killed and at least eight others injured in an explosion in the northern Sinai town of Rafah, eyewitnesses and medics said.
Eyewitnesses told an Al-Ahram Arabic news reporter that the attack took place early Thursday when suspected militants fired mortar shells at an army camp in Rafah.
Medics at the local Al-Arish Hospital said they received five bodies of army personnel following the incident. At least eight others were wounded, they added.
There was no immediate confirmation from Egypt's army spokesman of the deaths or how the attack took place.
Egyptian forces are grappling with an Islamist insurgency based in the northern part of the Sinai Peninsula, which spiked following the 2013 ouster of Islamist president Mohamed Morsi.
Hundreds of police and troops have since been killed in militant attacks.
The Egyptian army said in statement earlier Thursday it had killed three "terrorists" in an exchange of fire with forces in two separate incidents in northern Sinai.