Cairo - Seven militants were killed and 15 Egyptian military personnel were killed or wounded in a clash in North Sinai on Saturday, the Egyptian military said.

The breakdown of military casualties was not immediately clear. However, two security sources told Reuters that the some of the injuries were serious.

Security forces launched a campaign a year ago against Islamist militants focused on Egypt’s Sinai peninsula, and say they have killed several hundred militants since then.

“Combing operations and the pursuit and elimination of the terrorist elements in the area where the incident took place is ongoing,” the military spokesman said in a statement.

The security sources said operations were taking place under aerial cover.

Since 2013, Egyptian security forces have battled Islamist militants, who have repeatedly targeted security checkpoints and Egypt’s Christian minority.

Meanwhile, Egypt’s president has called on Western countries to boost efforts at tackling extremist ideology in online media and mosques.

Speaking at the Munich Security Conference Saturday, Abdul Fattah Al Sissi says countries must “tackle websites that are inciting hatred and spreading extremist and terrorist narratives among communities in the Islamic world and in the West.”

He also said authorities should “be very mindful of what is being promoted at houses of worship,” adding that extremists should not be allowed to preach. He underlined his efforts in Egypt to control the sermons in mosques.