The so-called Islamic State of Iraq and Syria (Isis) has claimed the Cairo bomb attack on 11 December, according to a statement from the Islamist group.
The bomb attack, which killed at least 26 people, targeted the St Marks cathedral in the Abassiya area of Cairo.
Isis named the attacker as Abu Abdallah al-Masri, although Egyptian president Abdul Fatah al-Sisi identified the attacker as Shafik Mahmoud Mohamed Mostafa during a speech at the funeral of those killed.
This followed two days after an attack on 9 December, when a roadside bomb killed six police officers at a police checkpoint in the Pyramids area of Cairo.
The two attacks are the biggest incidents to take place in civilian areas so far this year.
The local Islamist group The Hasm Movement has already taken responsibility for the Pyramid attack that killed six police officers.
The last major incident to take place in Cairo was when eight plain-clothed policemen were attacked in the Helwan district on 8 May.
Egypts security forces have been targeted by Islamist groups since the ousting of the Muslim Brotherhood in 2013, and have been involved in heavy fighting mostly in the Sinai region.
The latest attacks will do little for Egypts economy as it continues to struggle following years of limited revenues from tourism and foreign direct investments amid economic headwinds rooted in the countrys security status.