Anger is growing in the Egyptian capital after an explosion went off near the city's main Coptic Christian cathedral, killing at least 25 worshippers, many of them women and children.

Hundreds of Christians and Muslims protested outside St Mark's Cathedral, Cairo, late on Sunday, hours after the blast destroyed a female worshippers' hall at St Peter's church, which adjoins the cathedral - the seat of Egypt's Orthodox Christian Church.

The church's floor was covered in pools of congealed blood and debris from shattered windows, with ball bearings, apparently used as shrapnel inside the bomb, burrowing through furniture and peppering the walls.

The angry crowd chanted slogans against President Abdel Fattah el-Sisi and called for the dismissal of Magdy Abdel Ghaffar, the interior minister, whom they blamed for the security failure.

"The Ministry of Interior cannot protect our churches. It is time for us to protect ourselves," one Coptic protester standing at the church's metal gate said.

'No one came out safe'

Another Coptic protester said that security at the church was known to be lax, with guards reportedly "playing on the internet all day long.

"If we had dogs, it could have been better. Not a single one came out safe, not one. Shame on the Ministry of Interior and the police," said the protester.

Others chanted: "The people demand the fall of the regime", the rallying cry of the 2011 uprising that helped end Hosni Mubarak's 30-year rule.

Sisi's office condemned the attack, declaring three days of mourning and promising justice for the victims' families.

There was no immediate claim of responsibility, but supporters of the Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group celebrated the attack on social media.

Mohamad Elmasry, of the Doha Institute for Graduate Studies, said: "The attack against Coptic Christians is not an aberration."

Speaking to Al Jazeera, he said it "represents the continuation of a cycle of violence that has continued unabated since Egypt's July 2013 military coup.

"Since the coup, the Egyptian government and ISIL-affiliated 'terrorists' have traded attacks. The government has cast an unnecessarily wide 'terrorism' net, carrying out unprecedented human rights violations, including several mass killings, against moderate members of the political opposition."

Sharp escalation

The coup, which overthrew Mohamed Morsi, Egypt's first democratically elected president and a member of the Muslim Brotherhood, brought with it a sharp increase in violence, particularly in the Sinai region.

Egypt's Coptic Christians, who comprise about 10 percent of Egypt's 90 million people, often complain of discrimination and have been the target of religious violence.

"Perhaps, more than anything, today's attack demonstrates the extent to which Sisi, who came to power largely on a security platform, has failed to deliver on one of his most important campaign promises," Elmasry said.

Source: Al Jazeera and news agencies