Egypt’s President Abdel Fattah al-Sisi declared on Monday that a suicide bomber is responsible for the attack which killed 24 people at Cairo’s Coptic cathedral, the deadliest on the Christian minority in years. But Sisi did not name the organisation the attacker was believed to belong to, and no other group has claimed responsibility.

Speaking at a state funeral for the victims, Sisi said four people had been detained, including a woman, and security forces were seeking two more people believed to be involved. The bomber was a man wearing a suicide vest, he added.

Security sources said a bomb containing at least 12 kg of TNT exploded on a side of the church normally used by women.The Interior Ministry also released a picture of the bomber it identified as Mahmoud Shafik Mohamed Mostafa, 22, whose nom de guerre was Abu Dajjana al-Kanani. It also released an image of what it said was the battered head of the dead bomber, who hailed from the town of Fayyoum south of Cairo.

“The attack brought us great pain but we will never be torn apart,” President Sisi said. “We will only be much stronger. We will hold steadfast and, God willing, we will succeed,” he added.

At least 24 people were killed and 49 wounded when a bomb exploded in a chapel adjoining St Mark’s Cathedral, Cairo’s largest church and seat of the Coptic papacy, where security is normally tight.