Two gunmen on a motorbike assassinated a senior Egyptian Interior Ministry official outside his home in Cairo on Tuesday, security officials said, putting pressure on the military-backed government as it struggles to contain an Islamist insurgency.
"General Mohamed Saeed, head of the technical office of the minister of interior, was targeted by gunmen," said one of the officials.
Islamist militants have stepped up attacks on security forces since army chief Field Marshal Abdel Fattah al-Sisi toppled president Mohamed Morsi of the Muslim Brotherhood in July.
The assassination was carried out days before Sisi was expected to announce his candidacy for president. It also occurred hours before Morsi went on trial on charges of kidnapping and killing policemen after a 2011 jailbreak.
The Interior Ministry confirmed Saeed's killing. He was an aide to Interior Minister Mohamed Ibrahim, who survived an assassination attempt last year.
Political violence has hit investment and tourism hard in Egypt, the most populous Arab nation.
Militant groups based in the largely lawless Sinai Peninsula have killed hundreds of police and soldiers since Morsi's downfall. In the wake of his ouster, security forces also killed hundreds of his supporters on the streets of Cairo.
An Islamist insurgency appears to be taking root beyond Sinai. It took autocrat Hosni Mubarak several years to end an Islamist insurgency in the 1990s.
Last week, six people were killed in a wave of bomb attacks targeting policemen in Cairo. And a Sinai-based militant group brought down an army helicopter with a missile, killing five soldiers.