A bomb explosion near the Coptic Christian Cathedral in Egypt's capital, Cairo, has killed 25 people and wounded dozens.
The bomb tore through the Saint Peter and Saint Paul Church, which is adjacent to Saint Mark's Cathedral, the seat of the Coptic pope Tawadros II.
Some reports say a bomb was lobbed into a chapel adjacent to one of the cathedral's walls but others said it was planted inside.
State television reported that a security official said a bomb made of TNT appeared to have been the cause of the explosion.
Ambulances lined up outside the church in the capital's Abbasiya district to evacuate the dead and wounded.
A crowd gathered outside the church chanted: "Tell the sheikh, tell the priest, Egyptians' blood is not cheap".
There was no claim of responsibility for the attack, but jihadists in Sinai have targeted Christians before, as well as Muslims they accuse of working with the government.
Cathedral worker Attiya Mahrous, who rushed to the chapel after he heard the blast, said: "I found bodies, many of them women, lying on the pews. It was a horrible scene."
Another witness Mariam Shenouda said: "Everyone was in a state of shock. There were children. What have they done to deserve this? I wish I had died with them instead of seeing these scenes."
The head of al Azhar, Egypt's top Sunni authority, condemned the bombing.
Al Azhar's grand imam, Sheikh Ahmed al Tayeb, said in a statement: "The vile terrorist explosion was a great crime against all Egyptians."
The church "is deeply loved by many Coptic faithful in Cairo and it has a regular parish presence," said Bishop Angaelos, the General Bishop for the Coptic Church in Britain.
He said services had been held in the church on Sunday morning, while the adjacent St Mark's Cathedral was being renovated.
In April 2013, two people died in clashes outside St Mark's Cathedral.
Copts, who make up about 10% of Egypt's population of 90 million, have faced persecution and discrimination dating back to the 30-year rule of Hosni Mubarak, who was toppled by a popular uprising in 2011.
Dozens of people have been killed in recent years in sectarian attacks and clashes throughout Egypt.
Egypt has seen a wave of attacks by Islamic militants since the military overthrew President Mohammed Morsi, a freely elected leader who hailed from the Brotherhood, in 2013.
Many of Morsi's supporters blamed Christians for supporting the overthrow, and scores of churches and other Christian-owned properties in southern Egypt were ransacked that year.
The deadly attack on Sunday is the second to hit Cairo in two days.
Six policemen were killed on Friday in a bomb attack claimed by a group suspected by authorities of having links to the outlawed Muslim Brotherhood.