Islamic State claimed responsibility on Tuesday for a suicide bombing at Cairo's main Coptic cathedral and threatened more attacks against Christians.
The militant group said in a statement that a suicide bomber whom it identified as Abu Abdallah al-Masri had detonated his explosive belt inside the church.
"Every infidel and apostate in Egypt and everywhere should know that our war ... continues," the group said in the statement, published by its Amaq news agency.
The name it gave for the suicide bomber differed from that announced by Egyptian authorities on Monday - Mahmoud Shafik Mohammed Mostafa. It gave no explanation.
At least 25 people were killed in the attack and 49 wounded.