At least 25 people, mostly women, have been killed in an explosion inside Cairo’s Coptic cathedral on Sunday.
Forty-nine other worshippers were reportedly injured during the explosion, Egyptian state television reported.
Security sources told the Reuters news agency at least six children were among the dead.
The explosion reportedly occurred during church service at about 10am local time (0800GMT) at the St Peter and Paul Church adjacent to the St Mark Coptic cathedral.
Reuters cites security sources as saying a device containing about 12 kg of the explosive TNT had denoted on the women’s side of the cathedral.
There was no immediate claim of responsibility for the attack although supporters of the Islamic State group celebrated it on social media.
Egypt’s orthodox Copts who constitute about 10 percent of the country’s 90 million people, are the biggest Christian community in the Middle East.
The Copts have long complained of discrimination under successive Egyptian leaders saying they are poorly represented in the government and have also been kept out of many positions of justice.
The rise of Islamist activities in Egypt in the wake of Hosni Mubarak’s fall in February 2011 has worsened the marginalization of the Copts.
Islamists are waging an insurgency led by the so-called Islamic State’s branch in North Sinai where hundreds of soldiers and police have been killed.
The insurgents have also launched deadly attacks in Cairo and other cities.