The bomb went off during Sunday Mass at a chapel adjacent to St Mark's Cathedral

Egypt’s Coptic community held a funeral service on Monday for 25 Christians killed in a bombing the previous day at a church next to the main cathedral in Cairo — one of the deadliest attacks targeting the country’s religious minority in recent memory.

The bomb went off during Sunday Mass at a chapel adjacent to St Mark’s Cathedral, seat of the ancient Coptic Christian Church. No group has so far claimed responsibility for the attack.

The coffins of the victims were laid in front of the altar, with their names displayed on the side facing the congregation.

The spiritual leader of Egypt’s Orthodox Christians, Pope Tawadros II, led the service. At one point, he leaned on his staff and quietly prayed in front of the coffins. He had cut short a visit to Greece and flew home on Sunday after the bombing.

Only victims’ relatives were allowed to attend the service at the Virgin Mary and St Athanasius church in the eastern Cairo suburb of Nasr City. Some of them screamed out in grief, while the rest quietly sobbed or sat somberly during the service.

Scores of black-clad monks, bishops and priests of the Orthodox Church attended Monday’s service, which was carried live by state television and private TV networks.

Previously, the deadliest attack against Egypt’s Christians was a New Year’s Day bombing in 2011 in the Mediterranean city of Alexandria, for centuries the seat of the Orthodox Coptic Church. At least 21 were killed in that attack.

A state funeral was due later on Monday at a parade ground also in Nasr City, with President Abdel-Fattah el-Sissi in attendance.

Egypt has seen a wave of attacks by Islamic militants since 2013, when the military overthrew President Mohammed Morsi, a freely elected leader and a senior Muslim Brotherhood official. Many of his supporters blamed Christians for supporting his ouster, and scores of churches and other Christian-owned properties in southern Egypt were ransacked that year.

Since 2013, authorities have waged a sweeping crackdown, outlawing the Muslim Brotherhood, jailing thousands of mostly Islamist dissidents and killing hundreds in street clashes.

Egypt’s Christians have long complained of discrimination, saying they are denied top jobs in many fields, including academia and security forces.

The Church and many Christians have rallied behind el-Sissi, although there have been growing voices of dissent in the community. They say little has changed under his rule, with authorities failing to halt attacks on their churches and property.