Death toll of Monday's anti-police terror attack in the city of Arish in Egypt's North Sinai province had climbed to 18, state-run Ahram newspaper reported.
Seven others were wounded in the attack, said security and military officials.
Four armoured vehicles were destroyed due to roadside bombs and a fifth one carrying signal jamming equipment. The gunmen then opened fire on policemen.
Five police officers were injured in the shootout that took place in the neighbourhood of Agouza, Giza governorate, during a raid on two suspected terrorist hideouts, Sputnik reported. The wounded included a police brigadier general.
IS claimed it was behind the attack via its news agency Amaq.
The incident occurred some 30 kilometers west of Arish in northern Sinai, the heart of long-running militancy now led by the Velayat Sinai terror outfit.
The officials spoke on condition of anonymity because they were not authorised to speak to the media.
One source said authorities received a tip off about the hideouts of the individuals, who they suspect of being members of Hasm, a group which has claimed several attacks around the Egyptian capital targeting judges and policemen since previous year.
The suspects had fled from northern Sinai, a hotbed of militants, to Giza, where they planned to carry out terrorist attacks in the country, the ministry said.
Egypt has been suffering from a spike in terrorist attacks targeting civilians in the mainland over the past year. According to the military, thousands of militants have been killed in the operations held against them.
Monday's attack came a day after authorities said they had busted an extremist cell planning attacks in Cairo.
An anonymous security source told Al-Ahram that three militants have been killed in the attack as well.