Brigadier general among those injured in the attack near Arish, the provincial capital of North Sinai
Eighteen Egyptian policemen were killed in a bomb and gun attack on Monday near a security convoy in the north of the Sinai Peninsula, security and medical sources said.
The Islamic State, which is running a deadly insurgency in the area, claimed the attack through its propaganda arm, Amaq.
Security sources told Reuters that the dead included two officers. Three policemen and four ambulance workers were also injured in the attack, which started with a bomb and developed into a gun battle.
The attack near Arish, the capital of North Sinai province, wounded three others including a brigadier general who lost his leg.
The militants destroyed three armoured vehicles and a signal-jamming vehicle, according to reports.
An interior ministry statement said the bomb was hidden in a car that was being checked by officers.
"As the forces dealt with the car, it blew up," the ministry said, adding that the explosion was followed by gunfire from "militant elements hiding in the desert area alongside the road".
"This led to the martyrdom of some of the convoy's individuals and the injury of others," it said.
Security forces killed several militants in the gun battle near the explosion site, the MENA state news agency said.
An insurgency by the militant group has gained pace since the military toppled President Mohamed Morsi of the Muslim Brotherhood, Egypt's oldest Islamist movement, following mass protests against his rule in mid-2013.
Hundreds of soldiers and policemen have been killed since then.