0812 GMT October 06, 2022
The blaze started for unknown reasons at the Abu Sifine church in the capital's northwestern, working-class district of Imbaba, AFP reported.
President Abdel Fattah el-Sisi declared on his Facebook page: "I have mobilised all state services to ensure that all measures are taken."
Fire services later said the blaze had been brought under control.
The Egyptian Coptic Church reported "41 dead and 14 injured" citing "sources in the Ministry of Health", in a statement posted on its Facebook page.
The prosecutor's office said it had opened an investigation and sent a team to the scene to establish the cause of the blaze.
Copts are the largest Christian community in the Middle East, making up at least 10 million of Egypt's 103 million people.
Sisi, the first Egyptian president to attend the Coptic Christmas mass every year, recently appointed a Coptic judge to head the Constitutional Court for the first time in history.
Sisi said Sunday he had "presented his condolences by phone" to Coptic Pope Tawadros II, who has been the head of Egypt's Christian community since 2012.
Accidental fires are not uncommon in the sprawling megalopolis of Cairo, where millions of Egyptians live in informal settlements.
Egypt, with its often dilapidated and poorly maintained infrastructure, has suffered several deadly fires in recent years.
In March 2021, at least 20 people died in a blaze in a textile factory in an eastern suburb of Cairo.
In 2020, two hospital fires claimed the lives of 14 Covid-19 patients.