Pope Francis on Monday expressed his condolences on Monday to Coptic leader Tawadros II over the deadly blast at Cairo's main cathedral complex, telling him: "We are united in the blood of our martyrs."
During a phone-call to Tawadros II, Francis expressed his closeness to Egypt's Coptic community over Sunday's attack, which killed at least 25 people among them many women and children and wounded around 50 more.
Francis promised he would continue to pray for the Coptic community, according to a statement from the Vatican press office. On Sunday he condemned the "horrible" bombing in Cairo as well as other attacks in Turkey and Somalia at the weekend.
There was no immediate claim of responsibility for the bombing of the chapel at St Mark's Cathedral - the headquarters of the Coptic Orthodox church, and the home of Pope Tawadros II.
Officials from Egypt's exiled Muslim Brotherhood movement and home-grown militant groups condemned the attack, which was celebrated by supporters of the Islamic State jihadist group on social media.
The blast was one of the deadliest attacks carried out against the religious minority in recent years. It has angered Coptic Christians and Muslims alike, with some questioning whether the government is living up to its promise to provide security to all Egyptians..
Egypt has seen a rise in attacks by Islamist groups including those affiliated to IS since the army's overthrow of democratically elected Islamist president Mohammed Morsi in 2013.