Twenty-three people were killed after an explosion inside a church attached to the Coptic Cathedral in Cairo early Sunday, one of the deadliest attacks on Egyptian Christians in years.
Minister of Health Ahmed Emad said another 49, most of whom are believed to be Copts, were injured in the blast that took place in Abbassyia district near downtown.
"Twenty-nine people were discharged from hospitals after receiving treatment. Three people are still in a critical condition," the health ministry said in a statement.
A bomb went off in the small church of St Peter and St Paul (El-Botroseya), the Coptic Church's spokesman Rev Paul Halim told Al-Ahram Arabic news website.
The church was built in 1911 on the tomb of Boutros Ghali, who was Egypt's prime minister from 1908 to 1910.
The blast occurred in the church's ladies section, according to local media. The St Mark Cathedral was left undamaged.
"The explosion was caused by a 12 kilogramme TNT bomb," a security source told state news agency MENA.
Security forces have blocked the main roads surrounding the cathedral.
Hospitals where the injured are being treated, including Dar El-Shefaa and Ain Shams University Hospital, have called for blood donations, while calls on social media for people to donate have gone viral.
No one has claimed responsibility for the bombing so far. Islamist groups are waging an insurgency against the Egyptian state in North Sinai and sporadic attacks have occurred in Cairo and other governorates since Islamist president Mohamed Morsi was toppled in mid 2013.
Egyptian President Abdel-Fattah El-Sisi said that the country will observe three days of mourning following the explosion.
"Terrorism targets the country's Copts and Muslims... Egypt will only be made stronger and more united in such circumstances," President Sisi said in a statement.
He vowed to hold accountable the assailants and put on trial all who have "incited, facilitated or participated" in the terrorist attack.
The president described the Sunday church attack – as well as the Friday blast in Giza that left six policemen dead – as part of "a war against the great Egyptian people."
Russian President Vladimir Putin expressed his "shock and grief," particularly given the high number of women and children among the victims, Russian media said.
Al-Azhar, the world's oldest seat of Sunni Islamic learning, condemned the "terrorist attack that occurred this morning in the Saint Mark Cathedral in Abbasiya, which led to killings and injuries."
"Targeting houses of worship and the killing of the innocents are criminal acts that violate Islamic principles," Al-Azhar said in a statement.
Al-Azhar expressed full solidarity with the Egyptian Church and Egyptian Copts in the face of "terrorism."
The statement also expressed condolences to Egypt's Coptic Pope Tawadros II, to the families of the victims, and to all the Egyptian people, wishing a speedy recovery of the injured.
A church source told Al-Ahram that Pope Tawadros II has cut short his visit to Greece, and is on his way back to Cairo "to directly go to the location of the explosion."
After the explosion, dozens of Coptic and Muslim protesters gathered at the cathedral, chanting against the attack on the church in a show of both anger and unity.
The number of protesters increased on Sunday evening to several hundreds, with a group of them performing Coptic prayers near the site of the blast.
"We are not worried; our churches are open and prayers are continuing as normal. God is here for us," said Amira, who lives close to the protest site.
Waheed El-Attar, who has owned a medical supply shop adjacent to the church for over a year, says that despite the bombing, "Egypt is safe compared to a lot of countries."
Some protesters demanded the resignation of the interior minister, accusing him of dereliction, while others attempted to remove the cordon barricades around the cathedral, which led to minor skirmishes with security forces.
"I do not think today’s attack was targeting Christians. It is part of a series of terrorist attacks. There are [security] shortcomings," said Hani, a truck driver and brother of one the people injured in the blast.
Hani said that although his brother was wounded in the attack, he did not sustain any serious injuries.
"My brother… called us on the phone crying [after the explosion] and asking for our help." Hani’s brother was in the area to apply for a job, but headed to the church afterwards.
"My brother entered [the church] through the front doors without undergoing a security check. I will be staying [at the protest site] until [a government official] addresses the situation, even if it takes me days," he added.
"If my brother had died, there would have been no better place for him to die. I would have been upset, but also happy for him. If I could see myself or my family die for this country to get better, so be it."
Earlier in the day, a group of Muslim clerics joined the demonstration to show solidarity with the Coptic protesters.
Dina Shehab, who works with an emergency intervention team, said "we came here voluntarily after we heard the news this morning."
Shehab said that her team of 25 to 30 people offers first aid for those who might need it at the protest site, though she added that they have not witnessed any major injuries.
"The [protest] has been peaceful so far."
This is the third explosion this week; the previous two blasts targeted security personnel. On Friday, an explosion killed six policemen and injured three others in Giza's Haram district and another occurred in Kafr El-Sheikh international road, killing one civilian and injuring three policemen
There have been several attacks on churches following the 2013 dispersal of the Rabaa Al-Adawyia sit-in protesting the toppling of Morsi.
But one of the worst terrorist attacks against Copts in Egypt was in 2011 when 23 people were killed in an explosion at the Two Saints Church in Alexandria.