Egypt’s military launched air strikes against jihadist targets in the Sinai Peninsula on Saturday, the army said, after ISIS killed 12 soldiers at a checkpoint 40 km from the town of Bir al-Abd.

Friday’s attack saw mortar rounds and rockets fired at the army post that lies west of El-Arish, the provincial capital of North Sinai, according to officials.

It was the first major attack in the central Sinai area, which had so far escaped the militants’ campaign.

The northern Sinai is a stronghold of extremists, who have killed hundreds of soldiers and police since 2013.

The military said in a televised statement that its aircraft had taken off at dawn on Saturday for a reconnaissance and bombing mission that lasted several hours and was still ongoing.

It said the strikes targeted hideouts of armed extremists involved in Friday’s assault, adding that a number of the jihadists were killed and weapons destroyed.

The military has poured troops into the peninsula in recent years to battle the insurgency.

ISIS 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.

President Abdel Fattah al-Sisi describes militancy as an existential threat to Egypt.