Eight Egyptian sailors are missing after gunmen aboard a fishing boat fired on a navy ship Wednesday in the Mediterranean Sea.
Egyptian news agencies said five sailors were wounded in what officials were calling a terrorist attack.
Thirty-two of the gunmen have been captured, with one report saying four had been killed.
The Egyptian ship was on patrol off the coast of Damietta in the northeastern part of the country.
No one has claimed responsibility for the attack, which came just days after Egypt's main militant group, Ansar Beit al-Maqdis, declared allegiance to the Islamic State militants.
The militants have carried out attacks against the Egyptian military in the Sinai Peninsula.