Egyptian officials say a police officer was shot dead during an early morning operation against armed fighters on the outskirts of Cairo.
State television says security forces stormed the village of Kerdasah early Thursday, firing tear gas and exchanging gunfire with militants.
Officials say troops are looking to arrest those responsible for attacking police stations last month in violence that resulted in the deaths of 11 security officers.
Last month's violence in Kerdasah, an Islamist stronghold, came hours after security forces cleared two camps of supporters of deposed Islamist President Mohamed Morsi.
At least 1,000 people have been killed during the Egyptian military's crackdown against militants and supporters of Morsi and his Muslim Brotherhood. Egyptian officials have described the campaign as a "war on terror."
Highlighting that threat, Egyptian authorities on Thursday said they found two unexploded, primitive bombs that had been placed on the tracks of the Cairo Metro. State media said parts of the metro line have been shut down while authorities investigate.