(CNN) -- Two police officers were killed Monday while trying to detonate bombs found outside the Egyptian Presidential Palace, the interior ministry said.
Three bombs were found outside the palace in Cairo.
One officer died and three were wounded when one of the bombs exploded. A second officer died trying to defuse another bomb. That explosion injured several others, the ministry said.
The third bomb was successfully defused, Egypt's state-run new organization Al-Ahram reported.
Authorities do not know who placed the devices.
Militants in Egypt have stepped up attacks since the military's ouster last year of former President Mohamed Morsy, Egypt's first democratically elected top leader.
Last week, a series of small blasts hit metro stations and a courthouse in Cairo, injuring several people.
Egypt's former military chief Abdel Fattah el-Sisi has taken over as the country's president after winning 96% of the vote in the presidential election last month.