Egypt's military said on Thursday that the leader of the Islamic State group's affiliate has been killed in the Sinai Peninsula, along with several key aides and 45 other members of the extremist group.

Few details were immediately available and there was no word from the extremist group's branch in Egypt on what, if confirmed, would be a major setback for Sinai-based militants.

A posting on the Facebook page of the Egyptian military's chief spokesman, Brigadier General Mohammed Samir, said Abu Doaa al-Ansari was killed in an operation south of the coastal city of el-Arish. It said the operation was carried out by counterterrorism forces backed by warplanes and guided by "accurate intelligence".