Nine people, including six policemen, have been killed in a Cairo suburb near the pyramids when a makeshift bomb went off as police prepared to raid a militant hideout.
The Interior Ministry said that its security forces had arrived in their vehicles to raid a flat and found the building booby-trapped.
The device went off when they tried to defuse it. Ten people were wounded, the sources said.
Islamist militants have stepped up attacks on Egyptian soldiers and police since the army toppled president Mohammed Mursi of the Muslim Brotherhood in 2013, after mass protests against his rule.
Civilians have also been killed.