Gunmen shot dead three Egyptian policemen late on Monday night.
The attack took place at a security checkpoint just outside Cairo’s Al-Azhar university.
Eleven people are said to have been wounded.
The attack comes just a week before Egypt holds presidential elections in which former army chief Abdel Fattah al-Sisi is expected to win.
A witness described what happened:
“ The car was carrying four people, two in the front and two in the back. We saw a veiled woman in the car. All of them were wearing masks. They came from that direction and here the policemen were standing. They started shooting in every direction, and then went towards the cafe next door.”
Militants have stepped up attacks on security forces since al-Sisi removed Islamist President Mohamed Mursi from power last year and arrested thousands of Muslim brotherhood members.
Reporting for euronews Mohammed Shaikhibrahim said:
“ Today’s attack is one of a series of attacks specifically targeting police officers and it comes nearly a week before the presidential election, which makes the issue of security a priority in the dossier waiting for the next president. That’s because security is the key to stability and has an impact on all the other problems waiting for him.”