The decapitated bodies of two men were found by Egyptian security forces in a desert area in the northern Sinai peninsula early Sunday morning, days after a Sinai terrorist group announced it had beheaded four Egyptian men who they claimed had spied for Israel.

The two men had been kidnapped by unknown assailants a day before their bodies were discovered, residents of Rafah told Reuters’ Egyptian website, Aswat Masriya.

On Friday, villagers in Rafah, on the border with Gaza, discovered the beheaded corpse of a 23-year-old man who eyewitnesses said was kidnapped on Thursday near his house by gunmen driving an SUV, Aswat Masriya reported.

The severed head was reportedly placed in the mortuary of a nearby hospital as Egyptian police worked with local tribesmen in the restive peninsula to identify the perpetrators.

In a video released Thursday, Ansar Bayt al-Maqdis claimed responsibility for the execution and said the young man and three others had provided intelligence to Israel’s Mossad agency.

The video showed men in black masks beheading the accused collaborators as they knelt on the ground, according to Reuters.

The terror group said that the men provided intelligence to Israel used in a July airstrike on northern Sinai, in which three Ansar Bayt al-Maqdis fighters were killed. The Egyptian army said at the time of the strike that no Israeli aircraft had been in Egyptian airspace.

Two of the executed men served time in Israeli jails for smuggling, and two had said the Mossad had paid them for information, the group asserted in the video.

Earlier this month, the decapitated bodies of four other men were found in the Sinai Peninsula, with Egyptian security forces suspecting they had been killed for aiding the Egyptian army.

Egypt’s military has been carrying out a vast offensive against jihadist groups in the north of Sinai since militants stepped up attacks following the army’s ouster of Islamist president Mohammed Morsi in July last year.

Militants in northern Sinai, which also borders Israel and the Gaza Strip, have launched a number of attacks in retaliation for a government crackdown on supporters of Morsi.

At least 1,400 people have been killed in the crackdown, mostly Islamist supporters of Morsi.

The militant attacks usually target security forces, but they have also led to civilian casualties.

AFP and Lazar Berman contributed to this report.