Egyptian security officials and investigators inspect a bombing inside Cairo's Coptic cathedral in Egypt December 11, 2016. REUTERS/Amr Abdallah Dalsh

In a deadly attack on Egypt’s Christian minority, 25 people were at least killed as Cairo’s largest Coptic cathedral was bombed, while people were attending the Sunday mass.

A 12 kilogram TNT used for the purpose targeted one of the most symbolic religious sites for Copts, an ethno-religious group, also the largest religious minority in Egypt. However, the immediate cause of the bombing in yet unknown and so is the group or person responsible for the massive attack.

Whatever the intention of the attacker was, it surely has sent a pang of terror among the marginalised group, who allegedly face bias in the muslim dominated region. Ever since President Mohammed Morsi was overthrown in 2013 by the military, Morsi’s supporter blamed Christians for supporting the overthrow.

Hundreds of Copts gathered outside the church to demonstrate against the bombing on Sunday, as video footage from local media show the church property dismantled, with shards of furniture, and blood clots on the walls. Several groups and religious organisations condemned the act, as President Abdel Fattah El Sisi, declared a three-day national mourning. The UN Security Council urged “States, in accordance with their obligations under international law and relevant Security Council resolutions, to cooperate actively with all relevant authorities” to hold those accountable for this act of terrorism. While some home-grown militant groups condemned the attack, Islamic state supporters revelled in social media.