The Islamic State affiliate in Egypt says it has beheaded two men that it mistakenly described in a statement as priests, but were later identified by locals as leading religious figures from among Sinai's Bedouins.

Pictures were posted on the Twitter accounts of the group's supporters. They showed one of the men, elderly with a white beard and kneeling in an orange jumpsuit with his neck pressed against a steel stand. Masked IS executioners dressed in black raised long swords over his head.

Locals identified the man as the blind Sufi sheikh Suleiman Abu Heraz, who was abducted two weeks ago from his farm south of the peninsula's town of el-Arish. The second man was identified as sheikh Said Abdel-Fattah, a top Religious Endowment cleric abducted a month ago.