One of the security sources said authorities suspect the individuals to be members of Hasm, a group which has claimed several attacks around the Egyptian capital targeting judges and policemen since previous year.
The Egyptian military and police have killed hundreds of militants and arrested a similar number of suspects as part of the country's anti-terror war.More news: Rafal Majka Wins Stage 14, Chris Froome Maintains Lead
At least 18 policemen, two of them officers, died in the violence, and a brigadier general lost a leg in the blast, several sources at Arish hospital said.
The attack occurred near the town of El-Arish, administrative centre of province Northern Sinai. The officials spoke on condition of anonymity because they were not authorized to brief media.
In December 2016, Egypt's President Abdel Fattah al-Sisi named the 22-year-old Mahmoud Shafiq as the suicide bomber who attacked a church attached to Egypt's main Coptic Church in Cairo, killing more than 25 people. They said the fighters had sneaked into the capital from northern Sinai but did not say whether they were members of ISIL.More news: DT Aaron Donald Ends Holdout, Reports To Rams
Egypt accuses Hasm of being a militant wing of the Muslim Brotherhood, an Islamist group it outlawed in 2013.
Egypt has been fighting against a wave of terror activities that killed hundreds of policemen and soldiers since the military toppled former Islamist president Mohamed Morsi in July 2013 in response to mass protests against his one-year rule and his now outlawed Muslim Brotherhood group.
Today's attack came a day after Egyptian security forces killed 10 terrorists during a raid at their hideouts in a densely populated central Cairo neighbourhood.More news: Goa journalists union, Church body condemn Lankesh's murder