Egypt’s health ministry announced on Friday that the death toll from Sunday's St. Peter and St. Paul Church bombing in Cairo has risen to 26 after a 70-year-old woman who was caught in the blast died of her injuries, state news agency MENA reported.

Odette Saleh Mikhail died on Friday at Cairo's Demerdash Hospital.

Health minister advisor Sherif Wadie said that the number of injured victims who remain hospitalised stands at 23, three of whom remain in critical condition.

The initial death toll from the suicide attack was 23, mostly women, with 49 people injured.

The death toll rose to 25 by Monday.

Sunday's church bombing is one of the bloodiest attacks on churches in Egypt in years.

The explosion caused severe damage to parts of the church building.

The Egyptian government declared three days of mourning after the attack.

The Islamic State militant group claimed responsibility for the bombing in a statement issued on SITE intelligence group on Tuesday, bragging that it killed 80 "crusaders" in the suicide operation.

Egypt’s authorities has battling an Islamist insurgency in North Sinai for several years, mostly against Islamic State affiliate Ansar Beit Al-Maqdis, who regularly carry out deadly attacks against army and police personnel.