Egyptian officials investigating the massacre of worshippers at a mosque say the attackers were carrying the flag of the Islamic State group.
More than 300 people died in the assault in the northern Sinai province.
Imam Mohammed Abdelfatah says there seemed to be many attackers.
"About two minutes after I climbed onto the platform, I heard what sounded like an explosion outside the mosque," said Mr Abdelfatah.
"Then some people came inside firing at all the worshippers and they were hitting anybody and everybody - anyone that was breathing."