An officer was killed and three soldiers injured in an attack on an armored military vehicle in the tumultuous region of North Sinai, Al-Ahram Arabic news website reported.
The attack was carried out south of Al-Arish town on Tuesday morning.
Earlier on Tuesday, a civilian was killed and 42 army soldiers and two civilians injured in a militant attack on a security camp also in Al-Arish.
Egypt's army has been fighting a decade-long militant Islamist insurgency that has spiked since the ouster of president Mohamed Morsi in summer 2013. Hundreds of police and army forces have been killed in militant attacks.
The army said it has been intensifying its operations against militants in the region, saying it has killed dozens in recent weeks.