Armed gunmen attacked military checkpoints on the Sinai peninsula, leaving 15 Egyptian soliers and two civilians dead.
The checkpoints, located near the border with Gaza in the town of Sheikh Zuweid, were attacked on Thursday by militants suspected to be part of Sinai Province, a group which last year pledged allegiance to Islamic State.
Dozens of soldiers, militants and civilians have been killed already this year in northern Sinai.
Sinai Province was known as Ansar Beit al-Maqdi before it pledged allegiance to the leader of Islamic State, Abu Bakr al-Baghdadi.