Unknown gunmen killed three people and wounded another in the volatile Sinai Peninsula, a hotbed of Islamist insurgency, state news agency MENA reported late on Wednesday.

Security sources said the bodies of three men with gunshot wounds in the head and face were found in separate areas in the North Sinai town of Rafah.

Elsewhere in the town, a 23-year-old woman was injured in a gunshot attack while walking in the street, the sources added.

The bodies of the slain as well as the wounded were transferred to a local hospital.

Also on Wednesday, three headless bodies were found--among 5 corpses--in different parts of the Peninsula, the latest in a series of beheadings purportedly carried out by militant fighters.

Almost a dozen were found dead in the restive region this week, either beheaded or from gunshot wounds.

Egypt's army has struggled to crush militant violence based in the Peninsula that has spiked since the 2013 ouster of Islamist president Mohamed Morsi and at times expanded to mainland cities, including Cairo.

The army began late October demolishing houses and clearing residents in the Sinai border city of Rafah to set up a buffer zone, after 31 soldiers were killed in two militant attacks in Al-Arish, the deadliest violence on Egyptian troops in recent times.

Authorities said the move is aimed at deterring militant infiltration and arms smuggling.