The Islamic State has claimed responsibility for a suicide attack that killed 23 people during Mass at a church adjoining Cairo's main cathedral on Sunday.

The perpetrator of the attack was "a martyrdom seeker of the Islamic State," the group's Aamaq Agency media outlet said last night.

The bombing, in the complex that houses the seat of Pope Tawadros II, head of Egypt's Coptic Orthodox Church, was one of the worst ever on a Christian place of worship in Muslim-majority Egypt.

The victims were buried on Monday, after a funeral mass performed by Tawadros and a military ceremony headed by President Abdel-Fattah al-Sissi.

The Egyptian branch of Islamic State is active mainly in the Sinai Peninsula bordering Israel and the Gaza Strip, but has also carried out major attacks on security forces in Cairo and elsewhere.

In June it claimed responsibility for the murder of a priest in Sinai.

- dpa