Egypt's army said three of its personnel were killed and two wounded during air and ground operations against militants in the restive North Sinai region on Sunday.
Military air forces pounded 16 militant hideouts while ground and special troops simultaneously raided a number of other targets, killing 18 militants, military spokesman Brigadier General Mohamed Samir said in a statement.
Three military personnel were killed and two others wounded in the Sunday dawn fighting, he added.
The raids came two days after militants attacked an army checkpoint in the Bir Al-Abd area west of El-Arish, the provincial capital of North Sinai, killing 12 soldiers and wounding at least six more. The attack was claimed by the Egyptian affiliate of the Islamic State group.
The army said it killed 15 militant fighters in response when Egyptian jets bombed Islamist militant targets for three hours on Saturday.
Egyptian forces have in recent years been battling an Islamist insurgency based in parts of the northern Sinai region, which has mainly targeted police and troops.
Egyptian President Abdel-Fattah El-Sisi said in an interview with three public newspapers published on Saturday that his country's war against Islamic militants in the Sinai Peninsula would be long, but that conditions in the mountainous, thinly populated region were improving.
"The terrorists are evolving and we are improving our operations," he said.