The Islamic State group is increasingly recruiting Christian converts and has claimed responsibility for a mass killing in Egypt last month that killed dozens of Christians.
The group has been in Egypt since 2014.
It was established in the city of Mosul, Iraq, and has spread to Syria and Iraq, becoming a major threat to both countries.
IS is known to use Christian converts to carry out terrorist attacks.
A video released by the group last month claimed responsibility.
Egypt’s Interior Ministry said the attack occurred when Christians were praying outside a mosque.
It said an attacker opened fire and killed the worshippers.
The video was published on the group’s official Telegram account and included images of bloodied bodies.
The attack has raised concerns about the security of Christians in Egypt.
The ministry said it was working with Egypt’s intelligence agency to find the perpetrators.
The United States and other Western nations have also been worried about the spread of the group.
“The attacks in Egypt and Libya and the increasing support from ISIS-linked forces has raised the specter of increased attacks by ISIL-linked groups,” said Chris Woodcock, an expert on extremist groups at the Center for Strategic and International Studies.
“In the coming days, it’s likely that the United States will increase its engagement with Egyptian officials and authorities in an effort to combat the growth of ISIL and the growth in the number of extremists operating in Egypt.”