Egypt's military says the leader of the Islamic State's affiliate has been killed in the Sinai Peninsula.

A posting on the Facebook page of the military's chief spokesman, Brig-Gen Mohammed Samir, says Abu Doaa al-Ansari was killed in an operation guided by "accurate intelligence."

Thursday's posting says counterterrorism forces backed by war planes carried out the operation south of the coastal city of el-Arish.

It says several of al-Ansari's aides, along with 45 other members of the militant group, were also killed in the operation. The statement didn't say when the operation took place.

Egyptian forces have been battling Islamic militants in Sinai for years but the insurgency there has grown deadlier since the 2013 ouster by the military of the country's Islamist president.