Egypt said Monday it had arrested four people suspected of involvement in a devastating bombing on a Cairo Coptic church, as grief-stricken mourners gathered for the funeral of the 24 dead.

The bombing at the Saint Peter and Saint Paul Church on Sunday was the deadliest attack in recent memory on the Christian minority, who make up about 10 percent of Egypt's population.

Egypt mourns the death of 25 Christians killed in bombing


President Abdel Fattah al-Sisi, speaking at the funeral for those killed, said the attack was carried out by a suicide bomber who had been identified as 22-year-old Mahmoud Shafik Mohamed Mostafa.

"He blew himself up inside the church" with an explosive belt, Sisi said.

One of the four people arrested was a woman, Sisi said, and authorities were looking for two other suspects he did not identify.

Speaking to the Coptic Church's pope, Tawadros II, during the funeral, Sisi said: "We would not have been able to come to you today, your holiness, before getting some information."

The health ministry on Monday released a new death toll of 24 killed in the bombing of the church, one more fatality than what was reported the previous day.

Most of the victims were women, authorities have said.

The attack occurred during Sunday service at the church adjacent to Saint Mark's Cathedral, the seat of Tawadros II.

There has been no claim of responsibility for the bombing but Coptic Christians have been previously targeted in Egypt.

- Sisi leads mourners -

Wooden coffins, each bearing a cross, were covered with the Egyptian flag and lined up at the Saint Mary and Saint Athanasius Coptic Orthodox Church in Nasr City district on Monday.

A woman who lost two daughters in the bombing cried and fell to the ground next to their coffins while other mourners prayed silently.

In the streets of Nasr City, Sisi and Tawadros led mourners dressed in black behind soldiers carrying the coffins of the victims.

Troops marched in unison to the sound of military music.

"This blow has caused us a lot of pain, but never will we let it break us," Sisi said.

Sunday's blast shattered windows and scattered pews through the interior of the church, scorching its marble pillars.

Security officials said they believed a bomb containing 12 kilos (26 pounds) of TNT appeared to have been the cause of the explosion.

It was the worst attack on the Coptic Christian community since a 2011 suicide bombing killed more than 20 worshippers outside a church in the coastal city of Alexandria.

Copts have faced persecution and discrimination dating back to the 30-year rule of Hosni Mubarak, who was toppled by a popular uprising in 2011.

Islamists in August 2013 attacked churches and homes of Copts in retaliation for the dispersal by security forces of Cairo protest camps set up by supporters of Mohamed Morsi, the Islamist president deposed by then-army chief Sisi.

In October 2011, almost 30 people -- mostly Coptic Christians -- were killed after the army charged at a protest in Cairo to denounce the torching of a church in southern Egypt.