A policeman has been killed trying to defuse a bomb outside a Coptic Christian church in Egypt, security officials say.
Mustafa Abid was reportedly a specialist in mine clearance. The explosion injured two other officers and an onlooker.
The device was one of two hidden in a bag on a roof by the church in Nasr City outside Cairo.
It comes two days before Egypt's Christians celebrate their Christmas.
About 10% of Egypt's population are Copts, and many say the state discriminates against them and does not offer them enough protection.
Egyptian President Abdul Fattah al-Sisi - who declares himself a defender of Christians against extremists - is due to open Cathedral of Nativity on Sunday outside the capital, the day before Coptic Christmas on 7 January.
No group has of yet claimed the attack, but Islamist insurgents have regularly attacked Copts in the past. More than 100 have been killed in attacks by jihadists since 2016.
And the following month, police killed 19 Islamist militants who were accused of attacking Christians in a shoot-out.
Who are the Coptic Christians?
The Coptic Orthodox Church is the main Christian Church in Egypt. While most Copts live there, the church has about a million members outside the country.
Copts believe that their faith dates back to about AD50, when the Apostle Mark is said to have visited Egypt. The head of the church is called the Pope, and is considered to be the successor of Saint Mark.
The Coptic Church separated from other Christian denominations at the Council of Chalcedon in 451, in a dispute over the human and divine nature of Jesus Christ.
The current Coptic Pope, Tawadros II, stepped away from social media last month by closing his official Facebook page.