Egypt has been overwhelmed by condolences and a state of mourning over the deadly blast at a church in Cairo on Sunday that killed at least 23 Coptic worshipers and injured 49.

The blast took place in the morning at Saint Peter and Saint Paul Church, known as al-Boutrosiya Church, which is adjacent to Saint Mark’s Cathedrtal in Cairo’s Abassiya neighborhood.

Egyptian President Abdel-Fattah al-Sisi offered his condolences to Pope Tawadros II, head of Egypt’s Orthodox Church, about the tragic explosion, stressing it would not affect Egypt’s will to continue fighting terrorism.

“I have ultimate confidence in the ability of the Egyptian people, Muslims and Copts, to unite hand in hand to achieve victory in the war against terrorism,” said the Egyptian president.

For his part, the top pope asserted the solidarity and unity of the Egyptian people and their ability to confront such a distress, urging “fair retaliation against the perpetrators of such a painful terrorist crime.”

The Egyptian state TV mourned the tragedy’s “martyrs” in an aired full screen note with a black background while its channels marked the top left corner of the screen with a black line as a sign of mourning and grief.

Accompanied by the ministers of health and social solidarity, Prime Minister Sherif Ismail visited the scene, offered his condolences, met with the interior minister and instructed the police to intensify their efforts to find the perpetrators.

The cabinet condemned in a statement the terrorist blast and said “it will not affect the strength of the Egyptian national unity,” stressing the solidarity of all Egyptian Muslims and Copts in the face of “black terrorism.”

The attack came a day after an Egyptian top court confirmed the death sentence against a leading militant Islamist extremist Adel Habbara over a 2013 anti-military attack that killed at least 25 soldiers in restive North Siani province.

The deadly church blast also marked the day when Muslims celebrate the birthday of Prophet Muhammad around 1,500 years ago.

Al-Azhar, a world top body for Sunni Islamic learning in Egypt, also denounced the church bomb attack as “a big crime against all Egyptians,” stressing that the “cursed terrorism” targets Egypt’s stability and the unity of its people.

Likewise, the Fatwa Monitoring Observatory, a state-run anti-extremism thinktank, condemned the attack and said it meant “to turn the memory of the merciful Prophet’s birthday into an occasion of murder and bloodshed.”

Egypt has been facing a rising wave of terrorism since the military removed former Islamist President Mohamed Morsi in July 2013 following mass protests against his one-year rule and his now-outlawed Muslim Brotherhood group.

Security crackdown on Morsi’s followers left about 1,000 of them killed and thousands more arrested, while terrorist attacks killed several hundreds of police and military men, with most of the attacks claimed by a Sinai-based group loyal to the Islamic State (IS) regional terrorist group.

The Egyptian armed forces strongly condemned Sunday’s deadly church blast, mourning the victims of the “cowardly deed” and offering condolences to their family members.

“The armed forces assert that such acts will only increase the solidarity and unity of the Egyptian people to uproot terrorism and extremism,” military spokesman Mohamed Samir said in a statement.

Further, Egyptian Foreign Ministry’s spokesman Ahmed Abu Zeid said in a statement that “each attempt to subjugate the nation or seed strife among its citizens will only increase our strength and determination to continue construction and victory over every conspirator.”

The tragedy has been denounced by many other senior Egyptian officials including the ministers of culture, higher education, investment and industry as well as top lawmakers and party leaders.

Several states and world organizations condemned the church bombing and offered condolences to Egypt through official statements either from home or via their embassies in Cairo, including Russia, the United States, the European Union, Britain, France, Germany, Vatican, Saudi Arabia, Kuwait, Qatar, the United Arab Emirates, the Palestinian National Authority, Lebanon and Bahrain.