Tens of policemen gathered in the vicinity of the Minya University Hospital on Tuesday, protesting the murder of two policemen shot earlier during their service in front of a local church in Minya.
Masked men gunned down the two policemen earlier on Tuesday, killing them instantly.
Osama Abdel Moneim, a Minya prosecutor, ordered the quick arrest of those responsible and an investigation into the incident by Homeland Security (previously State Security). He also delegated the forensics team to perform an autopsy on the two bodies.
A military funeral was held for the two policemen, attended by Minya Governor Salah al-Din Zeyada.
The attack took place a day before the Coptic Christmas, due on January 7.
Militants have stepped up attacks targeting security forces in Egypt, particularly in the Sinai Peninsula, since the army's ouster of Islamist President Mohamed Mursi in July 2013, which followed mass protests against his rule.
A strong wave of attacks on churches closely followed the dispersal of two pro-Mursi sit-ins in August 2013.
According to the final report of the June 30 fact-finding committee, 64 churches were attacked nationwide in response to the dispersal, including 52 torched churches. The committee also reported the abduction of 140 Copts, and assaults which targeted 402 Coptic properties. It said most reprisal attacks took place in Minya.
The committee was established by former interim President Adly Mansour to investigate violent acts which took place since June 2013.