The northern Sinai is a stronghold of the Sunni extremists, who have killed hundreds of soldiers and police since the military overthrew Islamist president Mohamed Morsi in 2013.
Yesterday's attack saw mortar rounds and rockets fired at an army post west of El-Arish, the provincial capital of North Sinai, according to officials.
The military said in a televised statement that its aircraft had taken off at dawn today for a reconnaissance and bombing mission that lasted several hours and was still ongoing.
The military has poured troops into the peninsula in recent years to battle the insurgency.
IS has also targeted foreigners in Egypt and claimed last year's bombing of a Russian airliner carrying tourists home from a Sinai resort. All 224 people on board were killed.